add semicolon after CSSFontFaceRule for Fonts L3

Author: saschanaz

css-fonts-3/Fonts.src.html

@@ -4358,7 +4358,7 @@ <h3 id="om-fontface">The <code>CSSFontFaceRule</code> interface</h3>
 <pre class="idl">
 interface CSSFontFaceRule : CSSRule {
     readonly attribute CSSStyleDeclaration style;
-}</pre>
+};</pre>
 
 <h2 id="platform-props-to-css" class="no-num">Appendix A: Mapping platform font properties to CSS properties</h2>