Remove trailing double quote from link in GLTFState documentation

Remove the trailing double quote (") from the link
https://github.com/KhronosGroup/glTF/blob/main/specification/2.0/schema/asset.schema.json

Author: spoxii

classes/class_gltfstate.rst

@@ -32,7 +32,7 @@ Tutorials
 
 - :doc:`Runtime file loading and saving <../tutorials/io/runtime_file_loading_and_saving>`
 
-- `glTF asset header schema <https://github.com/KhronosGroup/glTF/blob/main/specification/2.0/schema/asset.schema.json">`__
+- `glTF asset header schema <https://github.com/KhronosGroup/glTF/blob/main/specification/2.0/schema/asset.schema.json>`__
 
 .. rst-class:: classref-reftable-group