[5.0][Foundation] Update hashing for bridged NSError protocols (#21205)

* [Foundation] Update hashing for bridged Error/NSError types

Protocols in resilient libraries that wish to provide a default implementation of hashing need to do so by providing a hash(into:) implementation.

hashValue has been deprecated as a Hashable requirement in SE-0206. Implementing only it in a protocol extension curses conforming types to get deprecation warnings by default.

(cherry picked from commit bbaec3d)

* [Foundation] _Bridged[Stored]NSError: Remove explicit impls for hashValue/_rawHashValue

The compiler-synthesized / stdlib-provided default implementations seem perfectly fine for these.

(cherry picked from commit 21d31ea)

* [Foundation] CocoaError.Code, URLError.Code: Remove hashValue implementation

These implementations did not produce the same hash values as the raw value. RawRepresentable provides a correct hashing implementation by default, so let’s just use that.

(cherry picked from commit 23188af)

Author: lorentey

stdlib/public/SDK/Foundation/NSError.swift

@@ -406,7 +406,9 @@ extension _BridgedNSError where Self.RawValue: FixedWidthInteger {
     self.init(rawValue: RawValue(_bridgedNSError.code))
   }
 
-  public var hashValue: Int { return _code }
+  public func hash(into hasher: inout Hasher) {
+    hasher.combine(_code)
+  }
 }
 
 /// Describes a bridged error that stores the underlying NSError, so
@@ -480,9 +482,9 @@ public extension _BridgedStoredNSError {
 }
 
 /// Implementation of Hashable for all _BridgedStoredNSErrors.
-public extension _BridgedStoredNSError {
-  var hashValue: Int {
-    return _nsError.hashValue
+extension _BridgedStoredNSError {
+  public func hash(into hasher: inout Hasher) {
+    hasher.combine(_nsError)
   }
 }
 
@@ -568,10 +570,6 @@ public struct CocoaError : _BridgedStoredNSError {
     public init(rawValue: Int) {
       self.rawValue = rawValue
     }
-    
-    public var hashValue: Int {
-      return self.rawValue
-    }
   }
 }
 
@@ -1799,10 +1797,6 @@ public struct URLError : _BridgedStoredNSError {
     public init(rawValue: Int) {
       self.rawValue = rawValue
     }
-
-    public var hashValue: Int {
-      return self.rawValue
-    }
   }
 }