🤖 labels: update Exercism-wide labels

[exercism-bot]

Summary:

• Fix the link to the Exercism-wide labels.
• Fix the x:type description, which was previously the same as that for x:knowledge.
• Improve the x:type/coding label description.
• Remove the reputation/contributed_code/<major|minor> labels. They are replaced by the x:size/<value> labels.
• Improve the wording of some other comments.

Upstream: https://github.com/exercism/org-wide-files/commit/53f167009e30

[ee7]

@ErikSchierboom could you approve this?