Fix tab size in code blocks again

Seems GitHub changed some selectors

extension/content.css

@@ -367,7 +367,9 @@ svg.octicon.octicon-star.dashboard-event-icon {
 .tab-size[data-tab-size='4'],
 .tab-size[data-tab-size='8'],
 .inline-review-comment,
-.gist table.lines {
+.gist table.lines,
+.highlight pre, /* Readme code blocks */
+.blob-code-inner /* PR inline diff */ {
 	tab-size: 4 !important;
 }