[TaskLocal] TL macro must handle force unwrapped optional types

Resolves rdar://128225191

lib/Macros/Sources/SwiftMacros/SyntaxExtensions.swift

@@ -30,4 +30,17 @@ extension VariableDeclSyntax {
       modifier.isAccessControl
     }
   }
+}
+
+extension ImplicitlyUnwrappedOptionalTypeSyntax {
+  internal var asOptionalTypeSyntax: some TypeSyntaxProtocol {
+    OptionalTypeSyntax(
+      leadingTrivia: leadingTrivia,
+      unexpectedBeforeWrappedType,
+      wrappedType: wrappedType,
+      self.unexpectedBetweenWrappedTypeAndExclamationMark,
+      self.unexpectedAfterExclamationMark,
+      trailingTrivia: self.trailingTrivia
+    )
+  }
 }