[gardening] Fix inconsistent headers. Fix typos. Fix a vs. an issues.

include/swift/AST/DeclContext.h

@@ -285,13 +285,13 @@ class alignas(1 << DeclContextAlignInBits) DeclContext {
 
   /// Gets the type being declared by this context.
   ///
-  /// - Generic types return an bound generic type using archetypes.
+  /// - Generic types return a bound generic type using archetypes.
   /// - Non-type contexts return a null type.
   Type getDeclaredTypeInContext() const;
 
   /// Gets the type being declared by this context.
   ///
-  /// - Generic types return an bound generic type using interface types.
+  /// - Generic types return a bound generic type using interface types.
   /// - Non-type contexts return a null type.
   Type getDeclaredInterfaceType() const;
 

include/swift/AST/GenericEnvironment.h

@@ -59,7 +59,7 @@ class GenericEnvironment final {
   /// Map an interface type to a contextual type.
   Type mapTypeIntoContext(ModuleDecl *M, Type type) const;
 
-  /// Map an generic parameter type to a contextual type.
+  /// Map a generic parameter type to a contextual type.
   Type mapTypeIntoContext(GenericTypeParamType *type) const;
 
   /// Derive a contextual type substitution map from a substitution array.

include/swift/AST/KnownStdlibTypes.def

@@ -1,4 +1,4 @@
-//===--- KnownStdlibTypes.cpp - Common standard library types -------------===//
+//===--- KnownStdlibTypes.def - Common standard library types ---*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //

stdlib/public/SDK/Foundation/NSValue.swift.gyb

@@ -1,4 +1,4 @@
-//===--- NSValue.swift - Bridging things in NSValue -----------------------===//
+//===--- NSValue.swift - Bridging things in NSValue -----------*- swift -*-===//
 //
 // This source file is part of the Swift.org open source project
 //

stdlib/public/SDK/QuartzCore/NSValue.swift.gyb

@@ -1,4 +1,4 @@
-//===--- NSValue.swift - Bridging things in NSValue -----------------------===//
+//===--- NSValue.swift - Bridging things in NSValue -----------*- swift -*-===//
 //
 // This source file is part of the Swift.org open source project
 //

stdlib/public/core/UnsafeRawBufferPointer.swift.gyb

@@ -1,4 +1,4 @@
-//===--- UnsafeRawBufferPointer.swift.gyb --------------------*- swift -*-===//
+//===--- UnsafeRawBufferPointer.swift.gyb ---------------------*- swift -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
@@ -65,7 +65,7 @@
 ///
 /// Example (continued):
 /// ```swift
-///   // Copy a another slice of memory back into the original slice.
+///   // Copy another slice of memory back into the original slice.
 ///   destBytes[0..<n] = someBytes[m..<(m+n)]
 /// ```
 ///

test/stdlib/UnsafeRawBufferPointer.swift

@@ -100,7 +100,7 @@ UnsafeRawBufferPointerTestSuite.test("empty") {
 }
 
 // Store a sequence of integers to raw memory, and reload them as structs.
-// Strore structs to raw memory, and reload them as integers.
+// Store structs to raw memory, and reload them as integers.
 UnsafeRawBufferPointerTestSuite.test("reinterpret") {
   struct Pair {
     var x: Int32