I suggest that
.templatesUsed .mw-redirect { font-style: italic; }
The rationale being that MediaWiki already italicizes redirects in other places, for example:
On Special:AllPages and Special:PrefixIndex (https://phabricator.wikimedia.org/source/mediawiki/browse/master/resources/src/mediawiki.special/mediawiki.special.css):
.allpagesredirect { font-style: italic; }
In the list of categories at the bottom of the page (https://phabricator.wikimedia.org/source/mediawiki/browse/master/resources/src/mediawiki.legacy/shared.css):
.catlinks li a.mw-redirect { font-style: italic; }
On category pages (https://phabricator.wikimedia.org/source/mediawiki/browse/master/resources/src/mediawiki.action/mediawiki.action.view.categoryPage.less):
.redirect-in-category { font-style: italic; }