Revert "Update colour contrast of commented code"

This reverts commit fcac0fb.

Author: marijnh

lib/codemirror.css

@@ -126,7 +126,7 @@
 .cm-s-default .cm-operator {}
 .cm-s-default .cm-variable-2 {color: #05a;}
 .cm-s-default .cm-variable-3, .cm-s-default .cm-type {color: #085;}
-.cm-s-default .cm-comment {color: #6b7884;}
+.cm-s-default .cm-comment {color: #a50;}
 .cm-s-default .cm-string {color: #a11;}
 .cm-s-default .cm-string-2 {color: #f50;}
 .cm-s-default .cm-meta {color: #555;}