[css-conditional-3] Remove markup from the changes secton, which was producing a normative ref to conditional-5. Fix #6964

Author: svgeesus

css-conditional-3/Overview.bs

@@ -1030,7 +1030,7 @@ The following (non-editorial) changes were made to this specification since the
       since without it they and the ensuing opening parenthesis will be tokenized as a function opening token.
   <li>Allowed the <code title=''>supports()</code> method
       to imply parentheses for simple declarations,
-      for consistency with the ''@import'' rule’s ''supports()'' function.
+      for consistency with the @import rule’s supports() function.
   <li>Fixed missing semicolons in IDL code.
   <li>Updated links, terminology, and example code in response to changes to other modules.
   <li>Spelling and grammatical corrections