Fix the fixits for dispatch_async and dispatch_group_async

They erroneously suggested `DispatchQueue.asynchronously`, but it's actually `DispatchQueue.async`.

Author: NachoSoto

stdlib/public/SDK/Dispatch/Private.swift

@@ -108,7 +108,7 @@ public func dispatch_data_copy_region(_ data: __DispatchData, _ location: Int, _
 	fatalError()
 }
 
-@available(*, unavailable, renamed:"DispatchQueue.asynchronously(self:group:qos:flags:execute:)")
+@available(*, unavailable, renamed:"DispatchQueue.async(self:group:qos:flags:execute:)")
 public func dispatch_group_async(_ group: DispatchGroup, _ queue: DispatchQueue, _ block: () -> Void)
 {
 	fatalError()
@@ -144,7 +144,7 @@ public func dispatch_apply(_ iterations: Int, _ queue: DispatchQueue, _ block: (
 	fatalError()
 }
 
-@available(*, unavailable, renamed:"DispatchQueue.asynchronously(self:execute:)")
+@available(*, unavailable, renamed:"DispatchQueue.async(self:execute:)")
 public func dispatch_async(_ queue: DispatchQueue, _ block: () -> Void)
 {
 	fatalError()