Add check Codeberg references

[charphi]

Add check Codeberg references.
See https://forgejo.org/docs/latest/user/linked-references/

The host engine is Forgejo which is a fork of Gitea.

Reference	Example
Issue	!123, #123, user/repo#123
Pull request	!123, #123, user/repo#123
Mention	@user_name
Commit	9ba12248

[charphi]

Examples from https://codeberg.org/forgejo/forgejo:

Ref	URL
#2613	https://codeberg.org/forgejo/forgejo/issues/2613
#2613 (comment)	https://codeberg.org/forgejo/forgejo/issues/2613#issuecomment-1654709
@0ko	https://codeberg.org/0ko
Codeberg/Community#1387	https://codeberg.org/Codeberg/Community/issues/1387
forgejo/forgejo#1119	https://codeberg.org/forgejo/forgejo/pulls/1119
d31d6d484c	https://codeberg.org/forgejo/forgejo/commit/d31d6d484c