[DOC] Tweaks for StringIO#isatty (#167) #564

Job	Run time
ruby-versions / Generate Ruby versions	5s
ubuntu-24.04 3.0	18s
ubuntu-24.04 debug	25s
ubuntu-24.04 3.2	18s
ubuntu-24.04 3.1	17s
ubuntu-24.04 3.4	14s
ubuntu-24.04 2.7	31s
ubuntu-24.04 3.3	18s
ubuntu-24.04 jruby-head	1m 6s
ubuntu-22.04 2.7	24s
ubuntu-24.04 head	18s
ubuntu-22.04 3.2	17s
ubuntu-24.04 truffleruby-head	26s
ubuntu-22.04 head	12s
ubuntu-22.04 3.3	15s
ubuntu-22.04 3.1	22s
ubuntu-22.04 truffleruby-head	26s
ubuntu-22.04 jruby-head	1m 5s
ubuntu-22.04 debug	19s
ubuntu-22.04 3.4	14s
ubuntu-22.04 3.0	15s
	8m 5s

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