Enforce a trailing slash on user profile links

[jonoaldersonwp]

As per #4561, we should ensure that links to user profiles include a trailing slash.

For example, but not conclusively, see:

• Translation contributor templates, like ​https://make.wordpress.org/polyglots/teams/?locale=fr_FR
• Props links in posts, like in ​https://wordpress.org/news/2020/06/wordpress-5-4-2-security-and-maintenance-release/
• Props lists in support articles, like in ​https://wordpress.org/support/wordpress-version/version-5-4-2/
• Props lists in articles, like in ​https://en-au.wordpress.org/2016/12/07/wordpress-4-7-vaughan/
• Legacy props lists, like in ​https://developer.wordpress.org/plugins/credits/

[dd32]

In 11373:

Consistently link to https://profiles.wordpress.org/$user/ with a trailing slash.

See #5810.

[dd32]

In 11374:

Consistently link to https://profiles.wordpress.org/$user/ with a trailing slash. Part 2.

See #5810.

[dd32]

In 11375:

Consistently link to https://profiles.wordpress.org/$user/ with a trailing slash. Part 3.

See #5810.

[dd32]

In 11376:

Consistently link to https://profiles.wordpress.org/$user/ with a trailing slash. Part 4.

See #5810.

[dd32]

In 11377:

Developer: Link credit @mention's to profiles.wordpress.org with a trailing slash.

See #5810.

[dd32]

The only things not done above are rosetta/localised blogposts:

Props lists in articles, like in ​https://en-au.wordpress.org/2016/12/07/wordpress-4-7-vaughan/

These aren't too hard to update, but there's a lot of sites that could have them in their post_content, which isn't a task for today.

[jonoaldersonwp]

Oh wow, amazing work! :)