fixup! Bug 16940: After update, load local change notes.

Bug 43081: Remove line-height for non-ASCII text.

browser/base/content/abouttbupdate/aboutTBUpdate.css

@@ -32,6 +32,9 @@ body > *:not([hidden]) {
 
 .content {
   grid-column: 2;
+}
+
+.content.en-US-content {
   font-family: monospace;
   line-height: 1.4;
 }

browser/base/content/abouttbupdate/aboutTBUpdate.js

@@ -77,6 +77,7 @@ function setContent(containerId, content, fillContent) {
   // Release notes are only in English.
   contentEl.setAttribute("lang", "en-US");
   contentEl.setAttribute("dir", "ltr");
+  contentEl.classList.add("en-US-content");
   if (fillContent) {
     fillContent(contentEl, content);
   } else {