Check docs are up to date

[ErikSchierboom]

Please check if your documentation files are still up-to-date.

The key documentation files to check are:

• docs/ABOUT.md
• docs/INSTALLATION.md
• docs/LEARNING.md
• docs/RESOURCES.md
• docs/TESTS.md
• exercises/shared/.docs/help.md
• exercises/shared/.docs/tests.md

There might be more.

Link check report

To help identify invalid links, we've automatically checked the links of all *.md files in this repo. This is the report of that check:

📝 Summary
---------------------
🔍 Total...........48
✅ Successful......47
⏳ Timeouts.........0
🔀 Redirected.......0
👻 Excluded.........0
🚫 Errors...........1

Errors in ./docs/RESOURCES.md
✗ https://metacpan.org/pod/distribution/Perl-Tidy/docs/stylekey.pod (HTTP status client error (404 Not Found) for url (https://metacpan.org/dist/Perl-Tidy/view/docs/stylekey.pod))

Tracking

https://github.com/exercism/v3-launch/issues/54

[m-dango]

Include exercises/shared/.docs/debug.md as mentioned in #461