Sidebar of docs has buggy layout

[jaladh-singhal]

Somehow layout of TARDIS Docs sidebar has changed:

• The headings like "Using TARDIS", "Physics of TARDIS", etc. are now in grey that used to be in blue.
• These headings are sticking to left side of browser window - the left margin that used to be there is missing
• The vertical margins around headings are also weird - there's no top margin and extra bottom margin

Pointers to debug

• Search if there's latest release in RTD-theme which introduced this bug for projects like TARDIS using certain config settings
• Search since which commit in TARDIS codebase this buggy layout has been introduced
• Probably, this can be fixed by writing custom css

[isaacgsmith]

See sphinx-doc/sphinx#9051 and sphinx-doc/sphinx#9053. This is not just us with this problem.