man: clarify that IOXyz= only applies to the unified hierarchy, and BlockIOXyz= to the legacy hierarchy

With this change for each setting we say which hierarachy it applies to briefly
in the first sentence of the description, plus in longer form in an extra
pargraph at the end, with a recommendation for the counterpart of the option in
the other hierarchy.

Also adds markup and the "=" suffix to all mentioned settings.

0 files changed, 0 insertions, 0 deletions