[Fix #1238] Add new `Rails/EnumSyntax` cop #286

Job	Run time
Prism	33s
JRuby 9.4	2m 36s
Check documentation syntax	10s
Ruby 2.7	37s
Check the oldest supported RuboCop version	26s
Ruby 3.0	33s
Ruby 3.1	33s
Ruby 3.2	23s
Ruby 3.3	23s
Ruby head	28s
	6m 42s

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