Closes#7862
This adds a note for the user profile settings page about the avatar constraints.
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/7998
Reviewed-by: 0ko <0ko@noreply.codeberg.org>
Co-authored-by: Thomas Böhler <witcher@wiredspace.de>
Co-committed-by: Thomas Böhler <witcher@wiredspace.de>