LU-4315 doc: update llapi-layout-[f-s] man page style

LU-4315 doc: update llapi-layout-[f-s] man page style

Updating files to match the new code style for Lustre manual pages as
enforced by 'contrib/scripts/checkpatch-man.pl'.

This also includes other changes like removing < > or { } for singular
required arguments and placing [ ] around optional ones as well as
making all arguments CAPITAL and italicized, literal arguments are
bolded. Lines over 80 characters should be split at the natural line
end rather than the word that goes over the limit as fewer lines will
need to be modified when making changes if each sentence is on it's
own line.

Only using features that appear in groff 1.22.3 as this is the
available version is CentOS 8.

Checked files:
- llapi_layout_free.3
- llapi_layout_get_by_fd.3
- llapi_layout_get_by_fid.3
- llapi_layout_get_by_path.3
- llapi_layout_get_by_xattr.3
- llapi_layout_ost_index_get.3
- llapi_layout_ost_index_reset.3
- llapi_layout_ost_index_set.3
- llapi_layout_pattern_get.3
- llapi_layout_pattern_set.3
- llapi_layout_pool_name_get.3
- llapi_layout_pool_name_set.3
- llapi_layout_stripe_count_get.3
- llapi_layout_stripe_count_set.3
- llapi_layout_stripe_size_get.3
- llapi_layout_stripe_size_set.3

Test-Parameters: trivial
Signed-off-by: Frederick Dilger <fdilger@whamcloud.com>
Change-Id: Ifdf0d86e76898bf3b4e7febb40acecb8f12ad702
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56173
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>