update rst doc link

Author: psifertex

docs/dev/documentation.md

@@ -23,7 +23,7 @@ To contribute to the Binary Ninja documentation, first sign the [contribution li
     echo API documentation available in build/html
 
 ## Changing
-Changing documentation for the API itself is fairly straight forward. Use [doxygen style comment blocks](https://www.doxygen.nl/manual/docblocks.html) in C++ and C, and [restructured text blocks](http://thomas-cokelaer.info/tutorials/sphinx/docstring_python.html) for python for the source. The user documentation is located in the `api/docs/` folder and the API documentation is generated from the config in the `api/api-docs` folder.
+Changing documentation for the API itself is fairly straight forward. Use [doxygen style comment blocks](https://www.doxygen.nl/manual/docblocks.html) in C++ and C, and [restructured text blocks](https://sphinx-tutorial.readthedocs.io/step-1/) for python for the source. The user documentation is located in the `api/docs/` folder and the API documentation is generated from the config in the `api/api-docs` folder.
 
 ???+ Info "Tip"
     When updating user documentation, the `mkdocs serve` feature is particularly helpful.