[css-2026] Add macOS UTI public.css, w3c#5310

Author: svgeesus

css-2026/Overview.bs

@@ -1050,7 +1050,7 @@ Additional information:
 	Deprecated alias names for this type: N/A
 	Magic number(s): N/A
 	File extension(s): .css
-	macOS Uniform Type Identifier(s): N/A
+	macOS Uniform Type Identifier(s): public.css
 	Windows clipboard name(s): N/A
 
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