This patch adds documentation for the symbols shown in the "Action(s)"
and "Altered" columns of `dnf history list`

The "Action(s)" column abbreviates the names of transaction actions when
there was more than one action, e.g. a transaction that both installs
and upgrades packages would be displayed as "I, U".

The "Altered" column prints some extra symbols when something unusual
happened with the transaction, like if any warnings were printed or if
it completed with a non-zero status.

Some language was taken from the yum man pages:
https://github.com/rpm-software-management/yum/blob/master/docs/yum.8.
It appears we no longer use the "P" or "s" symbols.

Resolves https://bugzilla.redhat.com/show_bug.cgi?id=2172067
(RhBug:2172067)

= changelog =
msg: Document the symbols in the output of `dnf history list`
type: bugfix
resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2172067

This change makes it resilient in some corner cases, such as if the user
has installed an old version of libdnf5 that doesn't provide
/etc/dnf/dnf.conf.

Also add missing escape before `.` for zck.

…rsed