Documentation: Clarifying the workflow of building the documentation

Remove navigating to the Documentation folder in the section description
for building the documentation, and add it to the first building steps.
Also remove the command to `cd Documentation` in the second steps, which
is necessary to properly install the dependencies to build the
documentation.

Documentation/contributing/documentation.rst

@@ -12,8 +12,7 @@ Using Sphinx, the RST files are rendered into HTML files that can be read in you
 Building
 ========
 
-To render the Documentation locally, you should clone the NuttX main repository, and
-go into ``Documentation`` directory. Then,
+To render the Documentation locally, you should clone the NuttX main repository and navigate into it. Then,
 
   1. Install Sphinx and other dependencies using pipenv.
      You may also find it helpful on platforms such as Windows and MacOS to use *pyenv*
@@ -21,8 +20,10 @@ go into ``Documentation`` directory. Then,
      project `site <https://github.com/pyenv/pyenv#installation>`_.
 
     .. code-block:: console
-
+      
       $ pip3 install pipenv
+      $ cd Documentation/
+      $ # install the dependencies into a virtual environment
       $ pipenv install
       $ # activate the virtual environment
       $ pipenv shell
@@ -31,7 +32,6 @@ go into ``Documentation`` directory. Then,
 
     .. code-block:: console
 
-      $ cd Documentation/
       $ make html
 
     The resulting HTMLs will end up under ``_build/html``. You can open your browser at the root with: