fix 2 dead links in README.md

README.md

@@ -2,7 +2,7 @@
 
 This repository contains the source files of [Godot Engine](https://godotengine.org)'s documentation, in reStructuredText markup language (reST).
 
-They are meant to be parsed with the [Sphinx](https://sphinx-doc.org/) documentation builder to build the HTML documentation on [Godot's website](https://docs.godotengine.org).
+They are meant to be parsed with the [Sphinx](https://www.sphinx-doc.org/) documentation builder to build the HTML documentation on [Godot's website](https://docs.godotengine.org).
 
 ## Contributing changes
 
@@ -42,7 +42,7 @@ Similarly, you can include attachments (like assets as support material for a tu
 
 ## Building with Sphinx
 
-To build the HTML website (or any other format supported by Sphinx, like PDF, EPUB or LaTeX), you need to install [Sphinx](https://sphinx-doc.org/) >= 1.3 as well as (for the HTML) the [readthedocs.org theme](https://github.com/snide/sphinx_rtd_theme). Only the Python 3 flavor was tested, though the Python 2 versions might work too.
+To build the HTML website (or any other format supported by Sphinx, like PDF, EPUB or LaTeX), you need to install [Sphinx](https://www.sphinx-doc.org/) >= 1.3 as well as (for the HTML) the [readthedocs.org theme](https://github.com/snide/sphinx_rtd_theme). Only the Python 3 flavor was tested, though the Python 2 versions might work too.
 
 Those tools are best installed using [pip](https://pip.pypa.io), Python's module installer. The Python 3 version might be provided (on Linux distros) as `pip3` or `python3-pip`. You can then run: