Small string fixes for encoding compatibility issues #380

Job	Run time
ruby-versions / Generate Ruby versions	2s
windows-latest 2.7	3m 13s
windows-latest 3.0	1m 11s
windows-latest 3.1	45s
windows-latest 3.2	1m 21s
windows-latest 3.3	1m 40s
windows-latest 3.4	1m 59s
windows-latest jruby-head	2m 7s
windows-latest mingw	1m 22s
windows-latest mswin	1m 42s
	15m 22s

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