Code Style Guidelines: Small fix

Removing mentions that SCons buildscripts use Python 2, and the distinction between 2 and 3, as the scripts should now work on both major versions... and it shouldn't make a difference for code style anyway.

community/contributing/code_style_guidelines.rst

@@ -129,8 +129,8 @@ Once a style is decided upon, it could also be enforced via clang-format.
 Python
 ------
 
-Godot's SCons buildsystem is written in Python 2, and various scripts included
-in the source tree are either in Python 2 or Python 3.
+Godot's SCons buildsystem is written in Python, and various scripts included
+in the source tree are also using Python.
 
 For those, we follow the `PEP-8 style guide <https://www.python.org/dev/peps/pep-0008/>`__,
 this is however not as strongly enforced as for the C++ code. If you are so