Be more defensive in how we insert our mkdocs media

[ericholscher]

This logic can be executed multiple times on some builds (see the mkdocs.yml):

https://github.com/rtfd/readthedocs.org/blob/ed8dd29a68d009fc08929fabf7155883482619c1/readthedocs/doc_builder/backends/mkdocs.py#L143-L152

If we have an issue reseting the branch/tag of the docs, we will end up inserting our media files twice, which causes them to be executed twice.

Solution

This code should check if one of the files we insert is already in the list:

if 'readthedocs-data.js' not in user_config.get('extra_javascript'):

[saadmk11]

Can I work on This Issue?
If I understood the problem correctly we need to add conditions for 'extra_javascript' and 'extra_css'
to check if the static files already exist in the user_config if not then add the files. Please Correct me if I'm Wrong.