Fix wiki linking behavior for markdown wiki pages
Related to #18019
- As per the documentation in !4372
## TODO
- [ ] !4432 Have wiki linking behave as per the documentation
- [x] Move `WikiLinkFilter` specs to the pipeline level
- [x] Verify current behavior on wiki `show` page
- [x] Fix current behavior on wiki `show` page
- [x] Verify current behaviour on wiki preview
- [x] Fix current behaviour on wiki preview
- [x] Rewrite all links and get preview links working
- [x] Make sure all links are on-par with the wiki `show` page
- [x] TDD `WikiLinkFilter` and get it working
- [x] Hook `WikiLinkFilter` up
- [x] Fix tests
- [x] Fix `markdown_spec`
- [x] Fix `wiki` spinach feature
- [x] Wait for [build](https://gitlab.com/gitlab-org/gitlab-ce/commit/4f50dd2/builds) to pass
- [x] Make sure all wiki-related pages are working as expected (history, all pages, etc.)
- [x] Test in different ruby versions
- [x] GitLab instances hosted on a relative URL
- [x] Non-markdown rendering formats?
- [x] RDoc
- [x] ASCIIDoc
- [x] Create issues to fix things for RDoc and ASCIIDoc
- [x] Gauge performance impact
- [x] Refactor
- [x] Re-organize commits
- [x] Make sure [build](f860e9a8dc/builds) passes
- [x] Respond to @rymai's comments
- [x] `class WikiLinkFilter < HTML::Pipeline::Filter`
- [x] blank line after guard clause
- [x] keyword arguments for `wiki` and `slug`
- [x] invert the condition
- [x] inline `user` in spec
- [x] Make sure spec names are not out of date
- [x] Comment for each rewrite rule
- [x] Add CHANGELOG entry
- [x] Reorganize commits
- [x] Make sure [build](19b91e749a/builds) passes
- [ ] Wait for merge
See merge request !4432
3d72cb897e