"Discussion" tab on wiki pages should have indication of non-existent target page (other than only color)
When a wiki page has no discussion page yet, this status is indicated by the red colour of the “Discussion” link in the tab at the top, but not by other means.
This is an accessibility blocker, because information conveyed by colour must also be indicated in text or markup: Priority 1 in WCAG 1.0 (http://www.w3.org/TR/WCAG10/wai-pageauth.html#tech-color-convey), Level A in WCAG 2.0 (http://www.w3.org/TR/WCAG20/#visual-audio-contrast-without-color).
This could be fixed simply by appending “(page does not exist)” to the title attribute as is done for red links in the body of a page, or by changing the title from “Discussion about the content page” to “Start discussion about the content page”.
Please see the screenshots in https://phabricator.wikimedia.org/T19099 . There is also an existing patch in Gerrit linked which provides some hints.
You are expected to provide a patch in Wikimedia Gerrit. See https://www.mediawiki.org/wiki/Gerrit/Tutorial for how to set up Git and Gerrit.