added the -webkit- prefix for font-feature-settings (mdn#23923)

css/properties/font-feature-settings.json

@@ -24,6 +24,11 @@
                 "version_added": "34",
                 "notes": "The <a href='https://mpeg.chiariglione.org/standards/mpeg-4/open-font-format/text-isoiec-cd-14496-22-3rd-edition'>ISO/IEC CD 14496-22 3rd edition</a> suggests using the <code>ssty</code> feature to provide glyph variants more suitable for use in scripts (for example primes used as superscripts). Starting with Firefox 29, this is done automatically by the <a href='https://developer.mozilla.org/docs/Web/MathML'>MathML</a> rendering engine. The ISO/IEC CD 14496-22 3rd edition also suggests applying the <code>dtls</code> feature to letters when placing mathematical accents to get dotless forms (for example dotless i, j with a hat). Starting with Firefox 35, this is done automatically by the MathML rendering engine. You can override the default values determined by the MathML rendering engine with CSS."
               },
+              {
+                "prefix": "-webkit-",
+                "version_added": "129",
+                "notes": "From Firefox 129 the <code>-webkit-font-feature-settings</code> alias has been added to support sites that are still supporting the vendor prefix."
+              },
               {
                 "prefix": "-moz-",
                 "version_added": "15",