fix(README): windows compilation instructions

What does this MR do?

Fixes style and instruction for windows documentation compilation

How to test it?

Read it?

README.md

@@ -20,11 +20,24 @@ Building the documentation with Windows
 =======================================
 
 In order to build this documentation, you will need to install Sphinx (especially the sphinx-build command).
-First, you need to install `Python <https://www.python.org/downloads/>`_
+First, you need to install [Python](https://www.python.org/downloads/)
 
-	- Add Python to your PATH	: SET PATH=%PATH%;C:\Python27
-	- Add Python Script    : SET PATH=%PATH%;C:\Python27\Scripts
-	- Use pip to install Sphinx    : pip install sphinx
+- Add Python to your PATH
+```
+SET PATH=%PATH%;C:\Python
+```
+- Add Python Script
+```
+SET PATH=%PATH%;C:\Python\Scripts
+```
+- Use pip to install Sphinx
+```
+pip install sphinx
+```
+- Use pip to install Sphinx rtd-theme
+```
+pip install sphinx_rtd_theme
+```
 
 Once sphinx is installed, launch the following command at the root of your local copy to generate html documentation:
 ```