MathJax formula at beginning of paragraph breaks in bullet lists

[jasagredo]

This code

-- | An example
--
-- - __A__:
--
--   \(X\)
--
-- - __B__:
--
--     \(X\)
--
-- - __C__:
--
--     \(X\) blah
--
-- - __D__:
--
--     blah
--     \(X\)
--
-- - __E__:
--
--     blah
--     blah \(X\)
--
-- - __F__:
--
--     blah
--      \(X\)
--
-- - __G__:
--
--     blah
--     \(X\) blah

Renders as:

• 🚫 in A, it seems we have to align the paragraph with the end of __ otherwise the paragraph is not regarded as belonging to the bullet point.
• ✔️ in B the formula as the first thing in the paragraph works.
• ✔️ in C we see it can be followed by anything and it works.
• 🚫 in D we see that if it is the first thing on a line but not the first thing of the paragraph it breaks.
• ✔️ in E we see that if we put something in front it works.
• ✔️ in F even just an space works.
• 🚫 in G putting something afterwards does not work.

I think this is also a manifestation of #774

[Kleidukos]

Hi, thank you for this PR, but Haddock now lives full-time in the GHC repository! Read more at https://discourse.haskell.org/t/haddock-now-lives-in-the-ghc-repository/9576.

Let me know if you feel it is still needed, and I'll migrate it. :)