This includes fixing some mistakes, as well as removing
redundant text that doesn't add new information, either because
it literally repeats what the code already says, or is actually
duplicated.
Change-Id: I3a8dd8ce57192deda8916cc444c87d7ab1a36515
Replace existing class with static ::search method
with a service under MediaWiki\User\ and with
dependencies injected
Similar to the creation of the SpecialPageFactory
service, rename the old file to UserNamePrefixSearch_deprecated
so that UserNamePrefixSearch.php can be used for
the service.
Follow-up patches will:
* Inject and use the new service
* Update the release notes
* Replace the use of the UserFactory with UserNameUtils
Change-Id: Ib78b9bdc96c935d75bd03a8af789b8b359c58b07
