cscott: Backport for [[gerrit:1271030|ParsoidLanguageConverter: convert inside <indicator> (T422961)]], [[gerrit:1271038|LanguageConverter: Allow disabling top-level variant "guess" (T419328)]] synced to the testservers (see https://wikitech.wikimedia.org/wiki/Mwdebug). Changes can now be verified there.