Steps to replicate the issue:
Go to the link for a user with an exclamation mark in their name but doesn't have a user page on the mobile site (e.g. https://en.m.wikipedia.org/wiki/User:!!!!)
What happens?:
Displays No user page for !!!! and This page should be created and edited by !!!! (hopefully Phabricator doesn't try to fix the display)
https://en.m.wikipedia.org/wiki/User:!!!!?uselang=qqx suggests it's an issue with the value the message uses rather than the message itself
It also seems to happen with question marks, semicolons and percent signs (e.g. https://es.m.wikipedia.org/wiki/Usuario:%3F_I%27m_a_person_"ordinary"_%3F)
What should have happened instead?:
Spaces should not be encoded
Other information (browser name/version, screenshots, etc.):
Chrome 122.0.6261.105
