docs: reduce excessive spacing in ToC for RST files

docs: reduce excessive spacing in ToC for RST files

The table of contents in the RST based files uses <p> tags inside the
<li>, which results in 1em's worth of spacing above & below each
entry. This results in way too much whitespace in the ToC.

Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>