NFSD: Docs: clean up pnfs server timeout docs

NFSD: Docs: clean up pnfs server timeout docs

Make various changes to the documentation formatting to avoid docs
build errors and otherwise improve the produced output format:

- use bullets for lists
- don't use a '.' at the end of echo commands
- fix indentation

Documentation/admin-guide/nfs/pnfs-block-server.rst:55: ERROR: Unexpected indentation. [docutils]
Documentation/admin-guide/nfs/pnfs-scsi-server.rst:37: ERROR: Unexpected indentation. [docutils]

Fixes: 6a97f70b45e7 ("NFSD: Enforce timeout on layout recall and integrate lease manager fencing")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>