Merge remote-tracking branch 'origin/bugfix/9749_fix_remaining_sphinx_errors'
Merge remote-tracking branch 'origin/bugfix/9739_py_fit_functions_missed'
Merge remote branch 'origin/feature/6972_offlinehelp_integration'
Fix category display names & links when generated on Windows.

The \-style separators were causing confusion as all paths need to be
relative unix-style paths.
Refs #9757
Merge branch 'bugfix/9757_docs_category_text_windows' into develop