Fix case-sensitiveness in :has-text() (regression)

Related feedback:
- https://www.reddit.com/r/uBlockOrigin/comments/zqot4i/is_there_a_way_to_show_only_element_with_specific/j0zl4ck/

src/js/contentscript-extra.js

@@ -41,7 +41,7 @@ const regexFromString = (s, exact = false) => {
         return new RegExp(match[1], match[2] || undefined);
     }
     const reStr = s.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
-    return new RegExp(exact ? `^${reStr}$` : reStr, 'i');
+    return new RegExp(exact ? `^${reStr}$` : reStr);
 };
 
 // 'P' stands for 'Procedural'