give credits to issue authors

src/about.html

@@ -25,9 +25,9 @@ ul {
     <li><a href="https://github.com/gorhill/uMatrix/issues" data-i18n="aboutIssues"></a><br>
     <li><span data-i18n="aboutContributors"></span><br>
         <ul>
-            <li><a href="https://github.com/gorhill/uMatrix/graphs/contributors">Github (uMatrix)</a>,
-                <a href="https://github.com/gorhill/httpswitchboard/graphs/contributors">Github (HTTP Switchboard)</a>
-            <li><a href="https://crowdin.net/project/umatrix">Crowdin</a>
+            <li>Code: <a href="https://github.com/gorhill/uMatrix/graphs/contributors">µMatrix, <a href="https://github.com/gorhill/httpswitchboard/graphs/contributors">HTTP Switchboard</a>
+            <li>Issues: <a href="https://github.com/gorhill/uMatrix/issues?q=is%3Aissue">µMatrix</a>, <a href="https://github.com/gorhill/httpswitchboard/issues?q=is%3Aissue">HTTP Switchboard</a>
+            <li>Translations: <a href="https://crowdin.net/project/umatrix">Crowdin</a>
         </ul>
 </ul>