* docs(branch.rst): Line number comments not needed

The topic `Branch Coverage Management` in this file
already has a setting:

        :linenothreshold: 5

Using this setting, sphinx will automatically provide
line numbers for code block longer than 5 lines.

reference: https://www.sphinx-doc.org/en/master/usage/restructuredtext/directives.html#directive-option-highlight-linenothreshold

* docs: Extra spaces in comment (maybe intentional)

The lines edited in this commit might have been given
extra indentation purposefully.
As they are an instruction for coverage py and are immediately
followed by another comment that is not for coveragepy.

* docs: inconsistent spaces in comments

Fix extra indentations or lack of indentations.

On the Test & Code podcast (https://testandcode.com/148) Brian Okken
explained why the old wording was confusing.  I hope this makes it
clearer.

auditwheel only installs on Python 3.  So only install it where we need
it, and clean up other .pip files along the way.