Fix some typos in docs and comments #106

Job	Run time
ci (tpb, ubuntu-22.04, --pb --threads --enable-libffi, test-some-fast)	29m 52s
ci (a6osx, macos-12)	16m 10s
ci (ta6osx, macos-12)	22m 18s
ci (i3le, ubuntu-22.04)	13m 0s
ci (ti3le, ubuntu-22.04)	16m 40s
ci (a6le, ubuntu-22.04)	8m 54s
ci (ta6le, ubuntu-22.04)	12m 2s
ci (ta6le, ubuntu-22.04, reboot, -m=ta6le --force, re.boot SCHEME="chezscheme", test-some-fast)	8m 27s
ci (i3nt, windows-2022, vs)	11m 45s
ci (ti3nt, windows-2022, vs)	14m 23s
ci (a6nt, windows-2022, vs)	12m 34s
ci (ta6nt, windows-2022, vs)	16m 10s
ci (ta6nt, windows-2022, gcc)	13m 7s
	3h 15m 22s

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