feat 🥁: implement special ordering for fontFace APIs

- Ensure 'src' property always appears first
- Sort remaining properties alphabetically
- Handle both APIs correctly despite different argument structures
- Handles font faces ordering the same in all 3 available CSS rules
- Update documentation with fontFace ordering details

src/css-rules/custom-order/rule-definition.ts

@@ -36,6 +36,8 @@ const customGroupOrderRule: Rule.RuleModule = {
     messages: {
       incorrectOrder:
         "Property '{{nextProperty}}' should come before '{{currentProperty}}' according to custom CSS group ordering.",
+      fontFaceOrder:
+        "Properties in fontFace should be ordered with 'src' first, followed by other properties in alphabetical order. Property '{{nextProperty}}' should come before '{{currentProperty}}'.",
     },
   },
   create(ruleContext: Rule.RuleContext) {