[DOC] Doc for StringIO#getbyte #543

Job	Run time
ruby-versions / Generate Ruby versions	8s
ubuntu-24.04 3.1	30s
ubuntu-24.04 3.2	31s
ubuntu-24.04 3.0	26s
ubuntu-24.04 3.4	14s
ubuntu-24.04 3.3	29s
ubuntu-24.04 2.7	37s
ubuntu-24.04 truffleruby-head	47s
ubuntu-24.04 jruby-head	1m 22s
ubuntu-22.04 2.7	34s
ubuntu-24.04 debug	32s
ubuntu-22.04 3.4	28s
ubuntu-24.04 head	25s
ubuntu-22.04 debug	33s
ubuntu-22.04 3.2	29s
ubuntu-22.04 3.1	25s
ubuntu-22.04 jruby-head	1m 16s
ubuntu-22.04 3.3	26s
ubuntu-22.04 3.0	26s
ubuntu-22.04 head	24s
ubuntu-22.04 truffleruby-head	38s
	11m 40s

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