fix: mypy problem with ragbits prompt output type (#772)

Author: mhordynski

packages/ragbits-core/src/ragbits/core/llms/base.py

@@ -364,6 +364,15 @@ async def generate_raw(
 
         return returned
 
+    @overload
+    async def generate(
+        self,
+        prompt: BasePromptWithParser[PromptOutputT],
+        *,
+        tools: None = None,
+        options: LLMClientOptionsT | None = None,
+    ) -> PromptOutputT: ...
+
     @overload
     async def generate(
         self,