[DOC] Tweaks for StringIO#pos= (#194) #617

Job	Run time
ruby-versions / Generate Ruby versions	4s
ubuntu-24.04 2.7	42s
ubuntu-24.04 3.0	15s
ubuntu-24.04 3.1	16s
ubuntu-24.04 3.3	20s
ubuntu-24.04 3.2	16s
ubuntu-24.04 debug	27s
ubuntu-24.04 truffleruby-head	29s
ubuntu-24.04 3.4	16s
ubuntu-24.04 jruby-head	1m 3s
ubuntu-24.04 head	18s
ubuntu-22.04 3.1	18s
ubuntu-22.04 3.0	16s
ubuntu-22.04 3.2	19s
ubuntu-22.04 3.3	20s
ubuntu-22.04 3.4	15s
ubuntu-22.04 2.7	46s
ubuntu-22.04 jruby-head	1m 3s
ubuntu-22.04 head	17s
ubuntu-22.04 truffleruby-head	24s
ubuntu-22.04 debug	25s
	8m 49s

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