Add missing "tw" entry to flags.mdx (#2226)

Co-authored-by: Paweł Kuna <[email protected]>

core/docs/ui/plugins/flags.mdx

@@ -293,6 +293,7 @@ The full list of countries can be found below.
   { "name": "Turkey", "code": "tr" },
   { "name": "Trinidad and Tobago", "code": "tt" },
   { "name": "Tuvalu", "code": "tv" },
+  { "name": "Taiwan", "code": "tw" },
   { "name": "Tanzania", "code": "tz" },
   { "name": "Ukraine", "code": "ua" },
   { "name": "Uganda", "code": "ug" },