code snippet additional character support

[onerandomusername]

This is a valid link to a snippet on GitHub https://github.com/astral-sh/uv-pre-commit/blob/571189337017c8bdbf22a0977b9e44d33b5e5ae9/.pre-commit-hooks.yaml#L11C1-L20C38

This should be considered in the codesnippets cog at least for github

IMO nothing special needs to be done for characters for github, as there's not a good way to portray that in discord, so we only need to fix the regex (and any additional handing)