LU-18967 doc: fix lctl-pool man pages

LU-18967 doc: fix lctl-pool man pages

Update the lctl-pool man pages to fix the following issues:
- lctl-pool_new: describe the POOLNAME formatting rules
- lctl-pool_remove: make OST index numbers consistent with pool_add
- lctl-pool_list: use a better POOLNAME example
- lctl-pool_destroy: use a better POOLNAME example
- lctl-pool_*: use a better example name for the pool

Fix up minor formatting issues in the man pages.

Test-Parameters: trivial
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: Ided7c79fbdcfb15aa01a1c2b66cf44292f500c1e
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/59062
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Frederick Dilger <fdilger@whamcloud.com>
Reviewed-by: Aryan Gupta <argupta@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>