LU-18110 doc: misspelled hexadecimal in lfs getstripe/getdirstripe

LU-18110 doc: misspelled hexadecimal in lfs getstripe/getdirstripe

Somehow hexadecimal is misspelled very consistently in
lfs getdirstripe and lfs getstripe manual pages as hexademical

Change-Id: Id2b2f96cec70728d06e533c61dea7745d7ccf910
Test-Parameters: trivial
Signed-off-by: Oleg Drokin <green@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55955
Reviewed-by: Frederick Dilger <fdilger@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>