journalctl: add -W as short for --no-hostname

--no-hostname is one of the switches I use very often. In particular,
when looking at CI logs, the hostname is almost never interesting.
-H is not yet used in journalctl, because journal operates locally, but
will want it if display of remote journals is implemented. Use -W.

shell-completion/bash/journalctl

@@ -47,7 +47,7 @@ _journalctl() {
                       --show-cursor --dmesg -k --pager-end -e -r --reverse
                       --utc -x --catalog --no-full --force --dump-catalog
                       --flush --rotate --sync --relinquish-var
-                      --smart-relinquish-var --no-hostname -N --fields
+                      --smart-relinquish-var --no-hostname -W -N --fields
                       --list-namespaces --list-invocations -I -v --verbose'
         [ARG]='-b --boot -D --directory -i --file -F --field -t --identifier
                       -T --exclude-identifier --facility -M --machine -o --output