WikiFormatting: add deprecation notice for `wiki_to_html`, `wiki_to_oneliner` and `wiki_to_outline`. Use the `format_to...` methods instead.
WikiFormatting: add deprecation notice for `wiki_to_html`, `wiki_to_oneliner` and `wiki_to_outline`. Use the `format_to...` methods instead.

There's no equivalent yet for `wiki_to_outline`, so this one should still be used for now.  For the next major version, where the most likely replacement API for this will be `format_to(env, 'outline', ...)`.

Closes #9183.


git-svn-id: f68c6b3b1dcd5d00a2560c384475aaef3bc99487@9427 af82e41b-90c4-0310-8c96-b1721e28e2e2

dafrito/trac-mirror,moreati/trac-gitsvn,exocad/exotrac,exocad/exotrac,dafrito/trac-mirror,exocad/exotrac,moreati/trac-gitsvn,dafrito/trac-mirror,dafrito/trac-mirror,exocad/exotrac,moreati/trac-gitsvn,moreati/trac-gitsvn