[gardening] Fix recently introduced typos

lib/Parse/ParseDecl.cpp

@@ -1738,9 +1738,9 @@ bool Parser::isStartOfDecl() {
   if (!isKeywordPossibleDeclStart(Tok)) return false;
 
   // When 'init' appears inside another 'init', it's likely the user wants to
-  // invoke a initializer but forgets to prefix it with 'self.' or 'super.'
+  // invoke an initializer but forgets to prefix it with 'self.' or 'super.'
   // Otherwise, expect 'init' to be the start of a declaration (and complain
-  // when the expectation is not fullfilled).
+  // when the expectation is not fulfilled).
   if (Tok.is(tok::kw_init)) {
     return !isa<ConstructorDecl>(CurDeclContext);
   }

stdlib/public/SDK/Foundation/NSStringAPI.swift

@@ -1314,7 +1314,7 @@ extension String {
   /// characters.
   @warn_unused_result
   public func addingPercentEncoding(
-    withAllowedCharaters allowedCharacters: NSCharacterSet
+    withAllowedCharacters allowedCharacters: NSCharacterSet
   ) -> String? {
     // FIXME: the documentation states that this method can return nil if the
     // transformation is not possible, without going into further details.  The

stdlib/public/core/Arrays.swift.gyb

@@ -325,7 +325,7 @@ public struct ${Self}<Element>
     return Builtin.castToNativeObject(_buffer.owner)
   }
 
-  // FIXME(ABI): move to an initalizer on _Buffer.
+  // FIXME(ABI): move to an initializer on _Buffer.
   static internal func _copyBuffer(buffer: inout _Buffer) {
     let newBuffer = _ContiguousArrayBuffer<Element>(
       uninitializedCount: buffer.count, minimumCapacity: buffer.count)

stdlib/public/core/CString.swift

@@ -57,7 +57,7 @@ extension String {
   public static func decodeCString<Encoding : UnicodeCodec>(
     cString: UnsafePointer<Encoding.CodeUnit>,
     as encoding: Encoding.Type,
-    repairingInvalidCodeUnits isReparing: Bool = true)
+    repairingInvalidCodeUnits isRepairing: Bool = true)
       -> (result: String, repairsMade: Bool)? {
 
     if cString._isNull {
@@ -68,7 +68,7 @@ extension String {
       start: cString, count: len)
 
     let (stringBuffer, hadError) = _StringBuffer.fromCodeUnits(
-      buffer, encoding: encoding, repairIllFormedSequences: isReparing)
+      buffer, encoding: encoding, repairIllFormedSequences: isRepairing)
     return stringBuffer.map {
       (result: String(_storage: $0), repairsMade: hadError)
     }

stdlib/public/core/Collection.swift

@@ -749,7 +749,7 @@ extension Collection {
     fatalError("unavailable function can't be called")
   }
 
-  @available(*, unavailable, message="Removed in Swift 3. Please use underestimatedCount peoperty.")
+  @available(*, unavailable, message="Removed in Swift 3. Please use underestimatedCount property.")
   public func underestimateCount() -> Int {
     fatalError("unavailable function can't be called")
   }

test/IRGen/enum_switch_singleton_enum_in_optional.sil

@@ -6,7 +6,7 @@ enum Optional<T> { case some(T), none }
 class AClass {
 }
 
-protocol  AProto {
+protocol AProto {
 }
 
 enum AnEnum {

test/Prototypes/CollectionTransformers.swift

@@ -24,7 +24,7 @@ public protocol ApproximateCountableSequence : Sequence {
   var approximateCount: ApproximateCount { get }
 }
 
-/// A collection that provides an efficient way to spilt its index ranges.
+/// A collection that provides an efficient way to split its index ranges.
 public protocol SplittableCollection : Collection {
   // We need this protocol so that collections with only forward or bidirectional
   // traversals could customize their splitting behavior.