[css-fonts-4] Clarify requirement for user addition/removal of fonts

Author: svgeesus

css-fonts-4/Overview.bs

@@ -4060,13 +4060,13 @@ UAs may alternatively choose
 to not initially expose any user-installed fonts to aid privacy on the web;
 for the set of installed fonts a user has installed
 is often used as a tracking vector to track users across the web.
-Users would then add to add to or remove fonts from that set,
+Users should then be able to add to or remove fonts from that set,
 according to their needs.
 
 UAs may choose a hybrid approach, where some user-installed fonts
 are initially exposed for internationalization,
 but others aren't.
-Again, users would be able to customise this starting set.
+Again, users should be able to customise this starting set.
 
 UAs are expected to make informed decisions
 on which fonts they expose to the web by default,