chore(macros/CSSRef): update "Using CSS math functions" slug (#10112)

Author: teoli2003

Diff for: kumascript/macros/CSSRef.ejs

@@ -1358,7 +1358,7 @@ async function buildPropertylist(pages, title) {
       <details>
           <summary><%=text['Math_functions']%></summary>
           <ol>
-            <li><%-smartLink(`${cssURL}CSS_Math_Functions/Using_CSS_math_functions`, null, text['Using_CSS_math_functions'], cssURL)%></li>
+            <li><%-smartLink(`${cssURL}CSS_Functions/Using_CSS_math_functions`, null, text['Using_CSS_math_functions'], cssURL)%></li>
           </ol>
       </details>
   </li>