Adjust left nav headings, hide design decisions pages (#65)

Author: devalog

fern/products/sdks/sdks.yml

@@ -5,11 +5,14 @@ navigation:
         path: ./introduction.mdx
       - link: Customer Showcase
         href: https://buildwithfern.com/showcase
+  - section: Generators
+    contents:
       - section: Typescript
         contents:
           - page: Quickstart
             path: ./overview/typescript/quickstart.mdx
           - page: Design Decisions
+            hidden: true
             path: ./overview/typescript/design.mdx
           - page: Configuration
             path: ./overview/typescript/configuration.mdx
@@ -25,6 +28,7 @@ navigation:
           - page: Quickstart
             path: ./overview/python/quickstart.mdx
           - page: Design Decisions
+            hidden: true
             path: ./overview/python/design.mdx
           - page: Configuration
             path: ./overview/python/configuration.mdx
@@ -40,6 +44,7 @@ navigation:
           - page: Quickstart
             path: ./overview/go/quickstart.mdx
           - page: Design Decisions
+            hidden: true
             path: ./overview/go/design.mdx
           - page: Configuration
             path: ./overview/go/configuration.mdx
@@ -55,6 +60,7 @@ navigation:
           - page: Quickstart
             path: ./overview/java/quickstart.mdx
           - page: Design Decisions
+            hidden: true
             path: ./overview/java/design.mdx
           - page: Configuration
             path: ./overview/java/configuration.mdx
@@ -70,6 +76,7 @@ navigation:
           - page: Quickstart
             path: ./overview/dotnet/quickstart.mdx
           - page: Design Decisions
+            hidden: true
             path: ./overview/dotnet/design.mdx
           - page: Configuration
             path: ./overview/dotnet/configuration.mdx
@@ -86,6 +93,7 @@ navigation:
           - page: Quickstart
             path: ./overview/php/quickstart.mdx
           - page: Design Decisions
+            hidden: true
             path: ./overview/php/design.mdx
           - page: Configuration
             path: ./overview/php/configuration.mdx
@@ -102,6 +110,7 @@ navigation:
           - page: Quickstart
             path: ./overview/ruby/quickstart.mdx
           - page: Design Decisions
+            hidden: true
             path: ./overview/ruby/design.mdx
           - page: Configuration
             path: ./overview/ruby/configuration.mdx
@@ -113,7 +122,7 @@ navigation:
             path: ./overview/ruby/custom-code.mdx
           - link: Customer Showcase
             href: https://buildwithfern.com/showcase
-  - section: Guides
+  - section: Deep Dives
     contents:    
       - page: Customize Method Names
         path: ./guides/customize-method-names.mdx