interpreter: use typed_pos_args for include_directories

mesonbuild/interpreter/interpreter.py

@@ -2269,9 +2269,10 @@ This will become a hard error in the future.''' % kwargs['input'], location=self
         return result
 
     @permittedKwargs({'is_system'})
-    @stringArgs
-    def func_include_directories(self, node, args, kwargs):
-        return self.build_incdir_object(args, kwargs.get('is_system', False))
+    @typed_pos_args('include_directories', varargs=str)
+    def func_include_directories(self, node: mparser.BaseNode, args: T.Tuple[T.List[str]],
+                                 kwargs: 'TYPE_kwargs') -> build.IncludeDirs:
+        return self.build_incdir_object(args[0], kwargs.get('is_system', False))
 
     def build_incdir_object(self, incdir_strings: T.List[str], is_system: bool = False) -> build.IncludeDirs:
         if not isinstance(is_system, bool):