Use <a> instead of <a href="#"> for JavaScript click events

* No status line with URL and "#".
* No new tab on middle click.

tabindex="0" ensures to have the normal tab order.

role="button" according to
https://www.mediawiki.org/wiki/Accessibility_guide_for_developers

Change-Id: I82f1923b3905f111ce7719c03a3919633271720a

UniversalLanguageSelector.hooks.php

@@ -387,7 +387,7 @@ class UniversalLanguageSelectorHooks {
 			'section' => 'personal/i18n',
 			// We use this class to hide this from no-JS users
 			'cssclass' => 'uls-preferences-link-wrapper',
-			'default' => "<a id='uls-preferences-link' href='#'>" .
+			'default' => "<a id='uls-preferences-link' role='button' tabindex='0'>" .
 				wfMessage( 'ext-uls-language-settings-preferences-link' )->escaped() . "</a>",
 		];