Concurrency: fix inconsistent _asyncLet_get signatures

Author: kateinoigakukun

stdlib/public/Concurrency/AsyncLet.swift

@@ -44,12 +44,12 @@ public func _asyncLetEnd(
 /// Wait if necessary and then project the result value of an async let
 @available(SwiftStdlib 5.1, *)
 @_silgen_name("swift_asyncLet_get")
-public func _asyncLet_get(_ asyncLet: Builtin.RawPointer, _ resultBuffer: Builtin.RawPointer) async -> Builtin.RawPointer
+public func _asyncLet_get(_ asyncLet: Builtin.RawPointer, _ resultBuffer: Builtin.RawPointer) async
 
 /// Wait if necessary and then project the result value of an async let that throws
 @available(SwiftStdlib 5.1, *)
 @_silgen_name("swift_asyncLet_get_throwing")
-public func _asyncLet_get_throwing(_ asyncLet: Builtin.RawPointer, _ resultBuffer: Builtin.RawPointer) async throws -> Builtin.RawPointer
+public func _asyncLet_get_throwing(_ asyncLet: Builtin.RawPointer, _ resultBuffer: Builtin.RawPointer) async throws
 
 /// Wait if necessary and then tear down the async let task
 @available(SwiftStdlib 5.1, *)

test/api-digester/stability-concurrency-abi.test

@@ -59,6 +59,10 @@ Func AsyncSequence.prefix(while:) is now with @preconcurrency
 Func MainActor.run(resultType:body:) has generic signature change from <T where T : Swift.Sendable> to <T>
 Func MainActor.run(resultType:body:) has mangled name changing from 'static Swift.MainActor.run<A where A: Swift.Sendable>(resultType: A.Type, body: @Swift.MainActor @Sendable () throws -> A) async throws -> A' to 'static Swift.MainActor.run<A>(resultType: A.Type, body: @Swift.MainActor @Sendable () throws -> A) async throws -> A'
 Func _runAsyncMain(_:) is now with @preconcurrency
+Func _asyncLet_get(_:_:) has mangled name changing from '_Concurrency._asyncLet_get(Builtin.RawPointer, Builtin.RawPointer) async -> Builtin.RawPointer' to '_Concurrency._asyncLet_get(Builtin.RawPointer, Builtin.RawPointer) async -> ()'
+Func _asyncLet_get(_:_:) has return type change from Builtin.RawPointer to ()
+Func _asyncLet_get_throwing(_:_:) has mangled name changing from '_Concurrency._asyncLet_get_throwing(Builtin.RawPointer, Builtin.RawPointer) async throws -> Builtin.RawPointer' to '_Concurrency._asyncLet_get_throwing(Builtin.RawPointer, Builtin.RawPointer) async throws -> ()'
+Func _asyncLet_get_throwing(_:_:) has return type change from Builtin.RawPointer to ()
 Protocol Actor has added inherited protocol AnyActor
 Protocol Actor has generic signature change from <Self : AnyObject, Self : Swift.Sendable> to <Self : _Concurrency.AnyActor>
 Struct CheckedContinuation has removed conformance to UnsafeSendable