Add text to TOC collapsible button label for accessibility.

- Provide message translations.
- Include other TOC message that was missing.

Bug: T310810
Change-Id: Ibd612b48ea3ef3f9f31f4bb5791c0cb82e447ece

i18n/en.json

@@ -44,6 +44,7 @@
 	"vector-anon-user-menu-pages-label": "Learn more about editing",
 	"vector-main-menu-tooltip": "Main menu",
 	"vector-toc-menu-tooltip": "Table of Contents",
+	"vector-toc-collapsible-button-label": "Toggle the table of contents",
 	"vector-article-tools-nav-label": "Tools",
 	"vector-site-nav-label": "Site",
 	"vector-2022-prefs-talkpage": "[[mw:Talk:Reading/Web/Desktop_Improvements|Discussion]]",

i18n/qqq.json

@@ -59,6 +59,7 @@
 	"vector-anon-user-menu-pages-label": "Accessible version of 'vector-anon-user-menu-pages' link text, prompts user to learn more about editing",
 	"vector-main-menu-tooltip": "Used as title attribute for main menu icon on hover.",
 	"vector-toc-menu-tooltip": "Used as title attribute for table of contents icon on hover.",
+	"vector-toc-collapsible-button-label": "Used as the label for the table of contents collapsible toggle button",
 	"vector-article-tools-nav-label": "Accessible label for the article tools nav landmark",
 	"vector-site-nav-label": "Accessible label for site (main menu) nav landmark",
 	"vector-2022-prefs-talkpage": "Link to the desktop improvements project talk page which is shown before the preview link in skin preferences. See T307113 for more information.",

includes/templates/ContentHeader.mustache

@@ -23,6 +23,7 @@
 		data-event-name="vector.toc-toggle-list"
 		tabindex="0"
 		title="{{msg-vector-toc-menu-tooltip}}">
+		{{msg-vector-toc-collapsible-button-label}}
 	</label>
 	{{/data-toc}}
     {{{html-title-heading}}}

skin.json

@@ -63,6 +63,8 @@
 						"vector-jumptocontent",
 						"vector-toc-beginning",
 						"vector-toc-heading",
+						"vector-toc-menu-tooltip",
+						"vector-toc-collapsible-button-label",
 						"vector-article-tools-nav-label",
 						"vector-site-nav-label",
 						"search",