Update links that are now in the Swiftlang org

Searched for https://github.com/apple throughout the repository, opened
each matching link, and replaced it with what it redirected to.

Author: amartini51

TSPL.docc/LanguageGuide/Macros.md

@@ -520,11 +520,11 @@ automatically includes a dependency on SwiftSyntax.
 If you're adding macros to an existing project,
 add a dependency on SwiftSyntax in your `Package.swift` file:
 
-[SwiftSyntax]: https://github.com/apple/swift-syntax/
+[SwiftSyntax]: https://github.com/swiftlang/swift-syntax
 
 ```swift
 dependencies: [
-    .package(url: "https://github.com/apple/swift-syntax", from: "509.0.0")
+    .package(url: "https://github.com/swiftlang/swift-syntax", from: "509.0.0")
 ],
 ```
 
@@ -633,7 +633,7 @@ so you can use this approach when implementing any kind of macro.
 <!--
 The return-a-string APIs come from here
 
-https://github.com/apple/swift-syntax/blob/main/Sources/SwiftSyntaxBuilder/Syntax%2BStringInterpolation.swift
+https://github.com/swiftlang/swift-syntax/blob/main/Sources/SwiftSyntaxBuilder/Syntax%2BStringInterpolation.swift
 -->
 
 

TSPL.docc/ReferenceManual/Attributes.md

@@ -752,7 +752,7 @@ Or are those supported today?
 I see #error and #warning as @freestanding(declaration)
 in the stdlib already:
 
-https://github.com/apple/swift/blob/main/stdlib/public/core/Macros.swift#L102
+https://github.com/swiftlang/swift/blob/main/stdlib/public/core/Macros.swift#L102
 -->
 
 ### frozen

TSPL.docc/ReferenceManual/Declarations.md

@@ -3582,7 +3582,7 @@ Call the `externalMacro(module:type:)` macro from the Swift standard library,
 passing in the name of a type that contains the macro's implementation,
 and the name of the module that contains that type.
 
-[SwiftSyntax]: https://github.com/apple/swift-syntax/
+[SwiftSyntax]: https://github.com/swiftlang/swift-syntax
 
 Macros can be overloaded,
 following the same model used by functions.

TSPL.docc/ReferenceManual/LexicalStructure.md

@@ -107,8 +107,8 @@ The backticks aren't considered part of the identifier;
 The paragraph above produces a link-resolution warning
 because of a known issue with ` in code voice.
 
-https://github.com/apple/swift-book/issues/71
-https://github.com/apple/swift-markdown/issues/93
+https://github.com/swiftlang/swift-book/issues/71
+https://github.com/swiftlang/swift-markdown/issues/93
 -->
 
 Inside a closure with no explicit parameter names,
@@ -133,8 +133,8 @@ The formal grammar below for 'identifier'
 produces a link-resolution warning
 because of a known issue with ` in code voice.
 
-https://github.com/apple/swift-book/issues/71
-https://github.com/apple/swift-markdown/issues/93
+https://github.com/swiftlang/swift-book/issues/71
+https://github.com/swiftlang/swift-markdown/issues/93
 -->
 
 > Grammar of an identifier:
@@ -971,7 +971,7 @@ and `/\d/` matches a single digit.
   of the supported syntax here.
   (Unified dialect/superset of POSIX + PCRE 2 + Oniguruma + .NET)
 
-  https://github.com/apple/swift-experimental-string-processing/blob/main/Sources/_StringProcessing/Regex/Core.swift
+  https://github.com/swiftlang/swift-experimental-string-processing/blob/main/Sources/_StringProcessing/Regex/Core.swift
 
   Regex literals and the DSL take different approaches to captures.
   The literals give you more type safety.

TSPL.docc/ReferenceManual/Types.md

@@ -975,7 +975,7 @@ because those types are already boxed protocol types.
 
 <!--
 Contrast P.Type with (any P.Type) and (any P).Type
-https://github.com/apple/swift-evolution/blob/main/proposals/0335-existential-any.md#metatypes
+https://github.com/swiftlang/swift-evolution/blob/main/proposals/0335-existential-any.md#metatypes
 -->
 
 > Grammar of a boxed protocol type:

TSPL.docc/header-staging.html

@@ -17,7 +17,7 @@ <h3>Important</h3>
         </p>
         <p>
             For the current shipping book, see <a href="https://docs.swift.org/swift-book/documentation/the-swift-programming-language/">Swift.org</a>.
-            To contribute to this documentation, see the <a href="https://github.com/apple/swift-book">swift-book project</a> on GitHub.
+            To contribute to this documentation, see the <a href="https://github.com/swiftlang/swift-book">swift-book project</a> on GitHub.
         </p>
         </aside>
     </div>