fix: Retain syntax highlighting when PR is updated (#30)

e.g. when a change is pushed and user clicks reload

Co-authored-by: Aidan Do <aidan.do@nqry.com.au>

static/content-script.js

@@ -4,7 +4,9 @@ const _diffFileSelector = "article[data-qa=pr-diff-file-styles]";
 runWhenUrlChanges(() => {
   const url = location.href;
   if (url.match(/https:\/\/bitbucket.org\/.+\/.+\/pull-requests\/.+/)) {
-    waitForElement('section[aria-label="Diffs"]').then((diffSection) => {
+    // "#pull-request-details" is used instead of "section[aria-label="Diffs"]" because the latter
+    // is replaced with a new element when the PR is updated (e.g. when a new change is pushed and user refreshes).
+    waitForElement('#pull-request-details').then((diffSection) => {
       allDiffsObserver.observe(diffSection, {
         childList: true,
         subtree: true,
@@ -13,8 +15,6 @@ runWhenUrlChanges(() => {
   }
 });
 
-
-
 const allDiffsObserver = new MutationObserver((mutations) => {
   mutations
     .filter((mutation) => mutation.type === "childList")