src: fix spelling typos in argp help text and error diagnostics

src: fix spelling typos in argp help text and error diagnostics

Since all these help text strings are marked for translation, apply the fixes
to translation strings as well, this helps to avoid translations becoming fuzzy.

lenght -> length
occured -> occurred
endianess -> endianness
reversable -> reversible

Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>