Added short keys -u and -m for --unescape and --mangle respectively. These short keys are present in systemd-escape --help output and are absent in man systemd-escape page.
<varlistentry>
<term><option>--unescape</option></term>
+ <term><option>-u</option></term>
<listitem><para>Instead of escaping the specified strings,
undo the escaping, reversing the operation. May not be used in
<varlistentry>
<term><option>--mangle</option></term>
+ <term><option>-m</option></term>
<listitem><para>Like <option>--escape</option>, but only
escape characters that are obviously not escaped yet, and