Merge pull request #45887 from bluikko/patch-3

doc: replace spaces with underscores in config option names

Reviewed-by: Anthony D'Atri <anthony.datri@gmail.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>

diff --cc doc/rbd/rbd-persistent-write-log-cache.rst
Simple merge