Fix single fetch types for synchronous loader/action functions

Author: brophdawg11

.changeset/violet-trains-change.md

@@ -0,0 +1,5 @@
+---
+"@remix-run/react": patch
+---
+
+[REMOVE] Fix return type when no promise is used

packages/remix-react/future/single-fetch.d.ts

@@ -36,10 +36,10 @@ type DataFunctionReturnValue =
 
 type LoaderFunction_SingleFetch = (
   args: LoaderFunctionArgs
-) => Promise<DataFunctionReturnValue>;
+) => Promise<DataFunctionReturnValue> | DataFunctionReturnValue;
 type ActionFunction_SingleFetch = (
   args: ActionFunctionArgs
-) => Promise<DataFunctionReturnValue>;
+) => Promise<DataFunctionReturnValue> | DataFunctionReturnValue;
 
 // Backwards-compatible type for Remix v2 where json/defer still use the old types,
 // and only non-json/defer returns use the new types.  This allows for incremental