macOS

Rename `f_optarg` to `f_opt_arg` for consistency in parser rules #618

Job	Run time
make (check, macos-14, --with-gcc=gcc-14)	6m 36s
make (check, macos-14, --with-jemalloc --with-opt-dir=$(brew --prefix jemalloc))	6m 12s
make (check, macos-15)	25m 22s
make (test-bundled-gems, macos-14)	7m 56s
make (test-bundler-parallel, macos-14)	15m 46s
make (check, macos-14)	5m 35s
make (test-all, --repeat-count=2, macos-14)	8m 34s
make (check, macos-13)	11m 26s
make (check, macos-14, --with-gmp)	5m 50s
macOS result	2s
	1h 33m 19s

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