meshgrid xy parameter should be literal

Author: crusaderky

src/array_api_stubs/_draft/creation_functions.py

@@ -20,6 +20,7 @@
 
 from ._types import (
     List,
+    Literal,
     NestedSequence,
     Optional,
     SupportsBufferProtocol,
@@ -454,15 +455,15 @@ def linspace(
     """
 
 
-def meshgrid(*arrays: array, indexing: str = "xy") -> List[array]:
+def meshgrid(*arrays: array, indexing: Literal["xy", "ij"]) -> List[array]:
     """
     Returns coordinate matrices from coordinate vectors.
 
     Parameters
     ----------
     arrays: array
         an arbitrary number of one-dimensional arrays representing grid coordinates. Each array should have the same numeric data type.
-    indexing: str
+    indexing: 'xy' | 'ij'
         Cartesian ``'xy'`` or matrix ``'ij'`` indexing of output. If provided zero or one one-dimensional vector(s) (i.e., the zero- and one-dimensional cases, respectively), the ``indexing`` keyword has no effect and should be ignored. Default: ``'xy'``.
 
     Returns