Update docs/starting/which-python.rst

Author: pluo

docs/starting/which-python.rst

@@ -50,7 +50,7 @@ level of compatibility with Python packages and C extension modules.
 
 If you are writing open-source Python code and want to reach the widest possible
 audience, targeting CPython is your best bet. If you need to use any packages
-that are rely on C extensions for their functionality (eg: numpy) then CPython
+that rely on C extensions for their functionality (eg: numpy) then CPython
 is your only choice.
 
 Being the reference implementation, all versions of the Python language are