Improve docstring wording of "for regular members" #3117
Description
This wording is weird but is consistent with the rest. Could benefit being updated consistently everywhere in a separate PR.
Originally posted by @Paillat-dev in #3109 (comment)
Several docstrings use wording like "for regular members", this a bit odd and hints at the existence of irregular members. Places these are used include the avatar, guild_avatar, guild_avatar_decoration and display_avatar_decoration functions in the Member class, and other guild_x attributes