Set initial focus on some special pages

* Special:Userrights - username (bug 43557)
* Special:Undelete - search prefix and reason (bug 43559)
* Special:BookSources - ISBN (bug 43561)

Bug: 43557
Bug: 43559
Bug: 43561
Change-Id: Idda08ffb3ca3d84d2adb89e5bc5f8e494d491486
Merge "Set initial focus on some special pages"