Issue/PR Context Popups (#9822)

* Add data-index attribute to issue anchors

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Init JS

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Add required data to anchor

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Finish popup

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Revert changes to html.go

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Better octicon contexts

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Split out popup function for re-use

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Style changes, test fixes, and cross-reference support

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Prefer em to px

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Move label margin to base CSS

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Move JS to separate file.

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Move JS to features and fix module

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Remove query-string and hash

Co-Authored-By: silverwind <me@silverwind.io>

Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: Antoine GIRARD <sapk@users.noreply.github.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: zeripath <art27@cantab.net>

web_src/js/index.js

@@ -5,6 +5,7 @@
 import './publicPath.js';
 import './gitGraphLoader.js';
 import './semanticDropdown.js';
+import initContextPopups from './features/contextPopup';
 
 function htmlEncode(text) {
   return jQuery('<div />').text(text).html();
@@ -2556,6 +2557,7 @@ $(document).ready(() => {
   initPullRequestReview();
   initRepoStatusChecker();
   initTemplateSearch();
+  initContextPopups(suburl);
 
   // Repo clone url.
   if ($('#repo-clone-url').length > 0) {