Add more grammars #339

Job	Run time
ruby-versions / Generate Ruby versions	5s
test (2.5, ubuntu-latest)	52s
test (2.5, macos-latest)	1m 21s
test (2.5, windows-latest)	4m 4s
test (2.6, ubuntu-latest)	53s
test (2.6, macos-latest)	1m 39s
test (2.6, windows-latest)	3m 32s
test (2.7, ubuntu-latest)	48s
test (2.7, macos-latest)	1m 29s
test (2.7, windows-latest)	2m 19s
test (3.0, ubuntu-latest)	32s
test (3.0, macos-latest)	53s
test (3.0, windows-latest)	1m 42s
test (3.1, ubuntu-latest)	33s
test (3.1, macos-latest)	58s
test (3.1, windows-latest)	2m 1s
test (3.2, ubuntu-latest)	27s
test (3.2, macos-latest)	58s
test (3.2, windows-latest)	2m 21s
test (head, ubuntu-latest)	24s
test (head, macos-latest)	50s
test (head, windows-latest)	2m 25s
test (jruby, ubuntu-latest)	7m 52s
test (jruby-head, ubuntu-latest)	6m 50s
test (truffleruby, ubuntu-latest)	2m 50s
test (truffleruby-head, ubuntu-latest)	3m 28s
	52m 6s

Provide feedback