Drop the bidi reset on CodeMirror lines

Bootstrap 5.3 no longer sets `unicode-bidi` on `pre`, so the reset added in fa33ee6 has nothing left to undo.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: hsbt

source/stylesheets/application.css.scss

@@ -258,11 +258,6 @@ pre {
     background: white;
     padding: .25em;
     border-radius: .5rem;
-
-    // Undo Bootstrap's bidi-override on pre, which lays out RTL text in logical order
-    pre {
-      unicode-bidi: normal;
-    }
   }
 }