Bug 1500164 - Allow selecting text in add-on release notes r=jaws

Differential Revision: https://phabricator.services.mozilla.com/D9139

--HG--
extra : moz-landing-system : lando

toolkit/mozapps/extensions/content/extensions.xml

@@ -1492,7 +1492,9 @@
     <handlers>
       <handler event="click" button="0"><![CDATA[
         if (!["button", "checkbox", "menulist", "menuitem"].includes(event.originalTarget.localName) &&
-            !event.originalTarget.classList.contains("text-link")) {
+            !event.originalTarget.classList.contains("text-link") &&
+            // Treat the relnotes container as embedded text instead of a click target.
+            !event.originalTarget.closest(".relnotes-container")) {
           this.showInDetailView();
         }
       ]]></handler>

toolkit/themes/shared/extensions/extensions.inc.css

@@ -364,6 +364,10 @@ richlistbox.list > richlistitem.addon {
   cursor: pointer;
 }
 
+.relnotes-container {
+  cursor: auto;
+}
+
 .addon-view[type="theme"] .icon {
   list-style-image: url("chrome://mozapps/skin/extensions/themeGeneric.svg");
 }