move string interpolation tutorial (#11646)

* move tutorial

Fixes MicrosoftDocs/feedback#1221

The string interpolation tutorial requires more background than the other introductory tutorials.

This PR moves those tutorials to the "exploration" section, where readers explore new C# features.

* fix build warnings

Author: BillWagner

.openpublishing.redirection.json

@@ -733,12 +733,12 @@
         },
         {
             "source_path": "docs/csharp/quick-starts/interpolated-strings-local.md",
-            "redirect_url": "/dotnet/csharp/tutorials/intro-to-csharp/interpolated-strings-local",
+            "redirect_url": "/dotnet/csharp/tutorials/exploration/interpolated-strings-local",
             "redirect_document_id": true
         },
         {
             "source_path": "docs/csharp/quick-starts/interpolated-strings.md",
-            "redirect_url": "/dotnet/csharp/tutorials/intro-to-csharp/interpolated-strings",
+            "redirect_url": "/dotnet/csharp/tutorials/exploration/interpolated-strings",
             "redirect_document_id": true
         },
         {
@@ -778,6 +778,14 @@
             "source_path": "docs/csharp/roslyn/index.md",
             "redirect_url": "/dotnet/csharp/roslyn-sdk/"
         },
+        {
+            "source_path": "docs/csharp/tutorials/intro-to-csharp/interpolated-strings-local.md",
+            "redirect_url": "/dotnet/csharp/tutorials/exploration/interpolated-strings-local"
+        },
+        {
+            "source_path": "docs/csharp/tutorials/intro-to-csharp/interpolated-strings.yml",
+            "redirect_url": "/dotnet/csharp/tutorials/exploration/interpolated-strings"
+        },
         {
             "source_path": "docs/csharp/tutorials/microservices.md",
             "redirect_url": "/dotnet/core/docker/",

docs/csharp/language-reference/tokens/interpolated.md

@@ -82,7 +82,7 @@ The following example uses implicit conversion to <xref:System.FormattableString
 
 ## Additional resources
 
-If you are new to string interpolation, see the [String interpolation in C#](../../tutorials/intro-to-csharp/interpolated-strings.yml) interactive tutorial. Or you can try the  [String interpolation in C#](../../tutorials/string-interpolation.md) tutorial locally on your machine.
+If you are new to string interpolation, see the [String interpolation in C#](../../tutorials/exploration/interpolated-strings.yml) interactive tutorial. Or you can try the  [String interpolation in C#](../../tutorials/string-interpolation.md) tutorial locally on your machine.
 
 ## See also
 

docs/csharp/programming-guide/strings/index.md

@@ -68,7 +68,7 @@ A string is an object of type <xref:System.String> whose value is text. Internal
  A format string is a string whose contents are determined dynamically at runtime. Format strings are created by embedding *interpolated expressions* or placeholders inside of braces within a string. Everything inside the braces (`{...}`) will be resolved to a value and output as a formatted string at runtime. There are two methods to create format strings: string interpolation and composite formatting.
 
 ### String Interpolation
-Available in C# 6.0 and later, [*interpolated strings*](../../language-reference/tokens/interpolated.md) are identified by the `$` special character and include interpolated expressions in braces. If you are new to string interpolation, see the [String interpolation - C# interactive tutorial](../../tutorials/intro-to-csharp/interpolated-strings.yml) for a quick overview.
+Available in C# 6.0 and later, [*interpolated strings*](../../language-reference/tokens/interpolated.md) are identified by the `$` special character and include interpolated expressions in braces. If you are new to string interpolation, see the [String interpolation - C# interactive tutorial](../../tutorials/exploration/interpolated-strings.yml) for a quick overview.
 
 Use string interpolation to improve the readability and maintainability of your code. String interpolation achieves the same results as the `String.Format` method, but improves ease of use and inline clarity.
 

docs/csharp/tutorials/intro-to-csharp/interpolated-strings-local.md renamed to docs/csharp/tutorials/exploration/interpolated-strings-local.md

@@ -9,7 +9,7 @@ ms.date: 10/23/2018
 
 This tutorial teaches you how to use C# [string interpolation](../../language-reference/tokens/interpolated.md) to insert values into a single result string. You write C# code and see the results of compiling and running it. The tutorial contains a series of lessons that show you how to insert values into a string and format those values in different ways.
 
-This tutorial expects that you have a machine you can use for development. The .NET topic [Get Started in 10 minutes](https://www.microsoft.com/net/core) has instructions for setting up your local development environment on Mac, PC or Linux. A quick overview of the commands you'll use is in [introduction to the local tutorials](local-environment.md), with links to more details. You also can complete the [interactive version](interpolated-strings.yml) of this tutorial in your browser.
+This tutorial expects that you have a machine you can use for development. The .NET topic [Get Started in 10 minutes](https://www.microsoft.com/net/core) has instructions for setting up your local development environment on Mac, PC or Linux. You also can complete the [interactive version](interpolated-strings.yml) of this tutorial in your browser.
 
 ## Create an interpolated string
 
@@ -161,6 +161,4 @@ The output looks something like the following:
 
 You've completed the string interpolation tutorial.
 
-You can continue with the [List collection](arrays-and-collections.md) tutorial in your own development environment.
-
 For more information, see the [String interpolation](../../language-reference/tokens/interpolated.md) topic and the [String interpolation in C#](../../tutorials/string-interpolation.md) tutorial.

docs/csharp/tutorials/intro-to-csharp/interpolated-strings.yml renamed to docs/csharp/tutorials/exploration/interpolated-strings.yml

@@ -9,8 +9,6 @@ metadata:
   level: Beginner
   displayType: two-column
   interactive: csharp
-  nextTutorialHref: list-collection.yml
-  nextTutorialTitle: Collections in C#
 items:
 - durationInMinutes: 2
   content: |

docs/csharp/tutorials/index.md

@@ -41,10 +41,6 @@ different actions. This tutorial is also available
 This tutorial assumes that you have finished the [Hello world](intro-to-csharp/hello-world.yml) and
 [Numbers in C#](intro-to-csharp/numbers-in-csharp.yml) lessons.
 
-## [String interpolation](intro-to-csharp/interpolated-strings.yml)
-
-The [String interpolation](intro-to-csharp/interpolated-strings.yml) tutorial shows you how to insert values into a string. You'll learn how to create an interpolated string with embedded C# expressions and how to control the text appearance of the expression results in the result string. This tutorial is also available [to run locally on your machine](intro-to-csharp/interpolated-strings-local.md).
-
 ## [List collection](intro-to-csharp/list-collection.yml)
 
 The [List collection](intro-to-csharp/list-collection.yml) lesson gives you
@@ -77,3 +73,6 @@ The following tutorials enable you to build C# programs using [.NET Core](../../
 * [Inheritance in C# and .NET](inheritance.md): demonstrates inheritance in C#, including the use of inheritance to define base classes, abstract base classes, and derived classes.
 * [Working with LINQ](working-with-linq.md): demonstrates many of the features of LINQ and the language elements that support it.
 * [Using Attributes](attributes.md): demonstrates how to create and use attributes in C#.
+* [String interpolation](exploration/interpolated-strings.yml) tutorial shows you how to insert values into a string. You'll learn how to create an interpolated string with embedded C# expressions and how to control the text appearance of the expression results in the result string. This tutorial is also available [to run locally on your machine](exploration/interpolated-strings-local.md).
+
+

docs/csharp/tutorials/intro-to-csharp/branches-and-loops-local.md

@@ -282,7 +282,7 @@ Try it yourself. Then check how you did. You should get 63 for an answer. You ca
 You've completed the "branches and loops" tutorial.
 
 You can continue with
-the [String interpolation](interpolated-strings-local.md) tutorial in
+the [Arrays and collections](arrays-and-collections.md) tutorial in
 your own development environment.
 
 You can learn more about these concepts in these topics:

docs/csharp/tutorials/intro-to-csharp/branches-and-loops.yml

@@ -9,8 +9,8 @@ metadata:
   ms.date: 08/24/2018
   displayType: two-column
   interactive: csharp
-  nextTutorialHref: interpolated-strings.yml
-  nextTutorialTitle: String interpolation in C#
+  nextTutorialHref: list-collection.yml
+  nextTutorialTitle: The list collection
 items:
 - durationInMinutes: 1
   content: |

docs/csharp/tutorials/intro-to-csharp/index.md

@@ -48,12 +48,6 @@ different actions. This tutorial is also available
 This tutorial assumes that you have finished the [Hello world](hello-world.yml) and
 [Numbers in C#](numbers-in-csharp.yml) lessons.
 
-## [String interpolation](interpolated-strings.yml)
-
-The [String interpolation](interpolated-strings.yml) tutorial shows you how to insert values into a string. You'll learn how to create an interpolated string with embedded C# expressions and how to control the formatting of the output string. This tutorial is also available [to run locally on your machine](interpolated-strings-local.md).
-
-This tutorial assumes that you have finished the [Hello world](hello-world.yml), [Numbers in C#](numbers-in-csharp.yml), and [Branches and loops](branches-and-loops.yml) lessons.
-
 ## [List collection](list-collection.yml)
 
 The [List collection](list-collection.yml) lesson gives you

docs/csharp/tutorials/intro-to-csharp/local-environment.md

@@ -43,12 +43,6 @@ different actions.
 This tutorial assumes that you have finished the [Hello world](hello-world.yml) and
 [Numbers in C#](numbers-in-csharp-local.md) lessons.
 
-## [String interpolation](interpolated-strings-local.md)
-
-The [String interpolation](interpolated-strings-local.md) tutorial shows you how to insert values into a string. You'll learn how to create an interpolated string with embedded C# expressions and how to control the formatting of the result string.
-
-This tutorial assumes that you have finished the [Hello world](hello-world.yml), [Numbers in C#](numbers-in-csharp-local.md), and [Branches and loops](branches-and-loops-local.md) lessons.
-
 ## [List collection](arrays-and-collections.md)
 
 The [List collection](arrays-and-collections.md) lesson gives you