interpreter: add another overload of source_strings_to_files

So that we can handle SourcesVarargsType

mesonbuild/interpreter/interpreter.py

@@ -3103,6 +3103,9 @@ class Interpreter(InterpreterBase, HoldableObject):
     @T.overload
     def source_strings_to_files(self, sources: T.List['SourceInputs'], strict: bool = True) -> T.List['SourceOutputs']: ... # noqa: F811
 
+    @T.overload
+    def source_strings_to_files(self, sources: T.List[SourcesVarargsType], strict: bool = True) -> T.List['SourceOutputs']: ... # noqa: F811
+
     def source_strings_to_files(self, sources: T.List['SourceInputs'], strict: bool = True) -> T.List['SourceOutputs']: # noqa: F811
         """Lower inputs to a list of Targets and Files, replacing any strings.