[API Notes] Use API notes rather than overlays to make error enums bridge.

The Clang attribute allows one to state that a particular enumeration
type describes an error, and associates it with a particular domain
constant. However, due to lack of API notes support, this attribute
wasn't actually getting used. Instead, we had a number of explicit
extensions to enum types to make them conform to the _BridgedNSError
protocol explicitly.

Now that we have API notes, use them to make these enums into error
enums with the appropriate domain, so that the Clang importer will
synthesize the _BridgedNSError conformances. Then, remove all of the
explicit conformances---and with them, the overlays for 12 frameworks.

There is a small fix to more eagerly consider these conformances as
"used" if an expression is formed with the error enum as a value
type. This better ensures that the conformances will be available at
runtime when needed.

This cleanup is needed to implement SE-0112 (NSError bridging),
although it is useful by itself.

Author: DougGregor

apinotes/AVFoundation.apinotes

@@ -243,3 +243,6 @@ Functions:
 Enumerators:
 - Name: AVMovieWritingAddMovieHeaderToDestination
   SwiftName: addMovieHeaderToDestination
+Tags:
+- Name: AVError
+  NSErrorDomain: AVFoundationErrorDomain

apinotes/CMakeLists.txt

@@ -3,15 +3,20 @@ set(SWIFT_API_NOTES_INPUTS
   AppKit
   AudioToolbox
   CloudKit
+  CoreBluetooth
   CoreData
   CoreGraphics
   CoreLocation
   CoreText
   Dispatch
+  EventKit
   Foundation
   GameKit
   HomeKit
+  Intents
+  LocalAuthentication
   MediaPlayer
+  MultipeerConnectivity
   NotificationCenter
   ObjectiveC
   PassKit
@@ -22,6 +27,7 @@ set(SWIFT_API_NOTES_INPUTS
   TVMLKit
   TVServices
   UIKit
+  WatchConnectivity
   WatchKit
   WebKit
   XCTest

apinotes/CloudKit.apinotes

@@ -44,3 +44,6 @@ Classes:
   - Selector: 'setParentReferenceFromRecordID:'
     MethodKind: Instance
     SwiftName: 'setParent(_:)'
+Tags:
+- Name: CKErrorCode
+  NSErrorDomain: CKErrorDomain

apinotes/Contacts.swift

@@ -0,0 +1,5 @@
+---
+Name: Contacts
+Tags:
+- Name: CNErrorCode
+  NSErrorDomain: CNErrorDomain

apinotes/CoreBluetooth.apinotes

@@ -0,0 +1,7 @@
+---
+Name: CoreBluetooth
+Tags:
+- Name: CBError
+  NSErrorDomain: CBErrorDomain
+- Name: CBATTError
+  NSErrorDomain: CBATTErrorDomain

apinotes/CoreLocation.apinotes

@@ -20,3 +20,6 @@ Protocols:
   - Selector: 'locationManager:didChangeAuthorizationStatus:'
     SwiftName: 'locationManager(_:didChangeAuthorization:)'
     MethodKind: Instance
+Tags:
+- Name: CLError
+  NSErrorDomain: kCLErrorDomain

apinotes/EventKit.apinotes

@@ -0,0 +1,5 @@
+---
+Name: EventKit
+Tags:
+- Name: EKErrorCode
+  NSErrorDomain: EKErrorDomain

apinotes/GameKit.apinotes

@@ -1,7 +1,11 @@
+---
 Name:            GameKit
 Classes:
   - Name: GKLocalPlayer
     Methods:
       - Selector:        'localPlayer'
         MethodKind:      Class
         FactoryAsInit:   C
+Tags:
+- Name: GKErrorCode
+  NSErrorDomain: GKErrorDomain

apinotes/HomeKit.apinotes

@@ -62,3 +62,6 @@ Classes:
   - Selector: 'initWithName:fireDate:timeZone:recurrences:'
     SwiftName: 'init(name:fireDate:timeZone:recurrences:)'
     MethodKind: Instance
+Tags:
+- Name: HMErrorCode
+  NSErrorDomain: HMErrorDomain

apinotes/Intents.apinotes

@@ -0,0 +1,5 @@
+---
+Name: Intents
+Tags:
+- Name: INIntentErrorCode
+  NSErrorDomain: INIntentErrorDomain