Documentation fixes

[abhro]

Checklist

• Appropriate tests were added
  (none necessary, only documentation changed)
• Any code changes were done in a way that does not break public API
• All documentation related to code changes were updated
• The new code follows the
  contributor guidelines, in particular the SciML Style Guide and
  COLPRAC.
• Any new documentation only uses public API

Additional context

Main changes

• Identify method headers in docstrings (indents)
• Use of backticks/monospace in names relating to code (and markdown deals with underscores as italics)
• Fix markdown lists