Small string fixes for encoding compatibility issues #378

Job	Run time
ruby-versions / Generate Ruby versions	1s
windows-latest 2.7	1m 39s
windows-latest 3.0	1m 20s
windows-latest 3.1	1m 25s
windows-latest 3.2	1m 22s
windows-latest 3.3	1m 21s
windows-latest 3.4	2m 6s
windows-latest jruby-head	3m 5s
windows-latest mingw	1m 25s
windows-latest mswin	1m 37s
	15m 21s

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