fix: semicolons are optional in entities

Author: amaanq

grammar.js

@@ -131,7 +131,7 @@ module.exports = grammar({
     // An entity can be named, numeric (decimal), or numeric (hexacecimal). The
     // longest entity name is 29 characters long, and the HTML spec says that
     // no more will ever be added.
-    entity: _ => /&(#([xX][0-9a-fA-F]{1,6}|[0-9]{1,5})|[A-Za-z]{1,30});/,
+    entity: _ => /&(#([xX][0-9a-fA-F]{1,6}|[0-9]{1,5})|[A-Za-z]{1,30});?/,
 
     quoted_attribute_value: $ => choice(
       seq('\'', optional(alias(/[^']+/, $.attribute_value)), '\''),