fix: remove unneeded main.html that added the dropdown menus at the bottom

[IzaakWN]

Issue

I realized at the bottom of the pages that used this plugin, the drop menus would be duplicated. For example:

https://cms-analysis.docs.cern.ch/ using mkdocs-header-dropdown v0.3.0:

https://tau-wiki.docs.cern.ch using mkdocs-header-dropdown v0.4.0:

Solution

It seems to be because partials/header-dropdown.html is included twice:

• once in templates/partial/header.html,
• and once in templates/main.html:

It seems the latter that adds the drop menu a second time to its script block at the very bottom of base.html. It is probably redundant, and additionally prevents the user from overriding main.html themselves for other purposes.

Therefore, this PR proposes to just remove templates/main.html all together. It works when I tested it locally for the CMS website. The dropmenu still appears in the header as expected, but not in the footer anymore.