[DOC] Fix various doc issues, improve the linter accordingly
This diff fixes a few issues:
- An obsolete content in the developer notes
- An invalid anchor in the Qt README
- Links to obsolete directories in the contrib README
The linter is updated to catch the cases 2 and 3. The link regex is
updated to allow for passing the anchors as well as links to directories
(or files without an extension). The gitian builder directory is
excluded as the README contains links relative to project root (starting
with /) which will raise false positives in our source tree.
Read the docs.
arc lint --everything
Revert the changes to src/qt/README.md and contrib/README.md and run
arc lint. Check the linter finds the issues.
Reviewers: #bitcoin_abc, jasonbcox
Reviewed By: #bitcoin_abc, jasonbcox
Differential Revision: https://reviews.bitcoinabc.org/D7436