[docs] fix typos

Author: WYK96

README.md

@@ -8,7 +8,7 @@
 
 <div align="center">
 
-[![Documentation](https://readthedocs.org/projects/xrviewer/badge/?version=latest)](https://xrtailor.readthedocs.io/en/latest/?badge=latest)
+[![Documentation](https://readthedocs.org/projects/xrviewer/badge/?version=latest)](https://xrviewer.readthedocs.io/en/latest/?badge=latest)
 [![Percentage of issues still open](https://isitmaintained.com/badge/open/openxrlab/xrviewer.svg)](https://github.com/openxrlab/xrviewer/issues)
 [![license](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://www.apache.org/licenses/LICENSE-2.0)