man: update '-b' option description to match '-a' and usage text

The usage text (syslogd -?) and the syslogd.8 man page was not in sync
wrt. the -b option.  This patch updates it to match the layout of -a,
the -a option is also slightly updated.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

man/syslogd.8

@@ -137,7 +137,7 @@ even if the host has more than one A or AAAA record.
 If this option is specified,
 .Nm
 tries to send the message to all addresses.
-.It Fl a Ar address[/len][:service] | Fl a Ar domainname[:service]
+.It Fl a Ar peer
 Allow peers to log to this syslogd using UDP datagrams.  Multiple
 .Fl a
 options may be specified.  Any
@@ -146,9 +146,11 @@ option is ignored if the
 .Fl s
 option is also specified.
 .Pp
-The peer argument may be any of the following:
+The
+.Ar peer
+argument may be any of the following:
 .Bl -tag -width 'address[/len][:service]'
-.It Ql address[/len][:service]
+.It address[/len][:service]
 Accept datagrams from IP
 .Ar address ,
 which can be specified as an IPv4 address or as an IPv6 address enclosed
@@ -175,7 +177,7 @@ otherwise.  If
 is an IPv6 address, a missing prefix
 .Ar len
 will be substituted by 128.
-.It Ql domainname[:service]
+.It domainname[:service]
 Accept datagrams where the reverse address lookup yields
 .Ar domainname
 for the sender address.  The meaning of
@@ -185,31 +187,31 @@ is as explained above.
 can contain special characters of a shell-style pattern such as
 .Ql * .
 .El
-.It Xo
+.It Fl b Ar name
+Bind to a specific address and/or port.  By default,
+.Nm
+listens on all interfaces on UDP port 514, unless started with the
+.Fl s
+option.  Multiple
 .Fl b
-.Sm off
-.Ar address Op \&: Ar service
-.Sm on
-.Xc
-.It Xo
-.Fl b
-.Sm off
-.Li \&: Ar service
-.Sm on
-.Xc
-Bind to a specific address and/or port.
-The address can be specified as a hostname,
-and the port as a service name.
-If an IPv6 address is specified, it should be enclosed with
+options may be specified to bind to several addresses and/or ports.
+.Pp
+The
+.Ar name
+argument may be any of the following:
+.Bl -tag -width 'address[/len][:service]'
+.It address[:port]
+The address can be specified as a hostname or an IP address, and the
+port as a service name or port number.  If an IPv6 address is specified,
+it should be enclosed with
 .Ql \&[
 and
 .Ql \&] .
-The default
-.Ar service
-is
-.Ql syslog .
-This option can be specified multiple times to bind to
-multiple addresses and/or ports.
+.It :port
+Service name or UDP port number.  The default service is
+.Ql syslog
+(UDP), port 512.
+.El
 .It Fl C Ar file
 File to use for caching last read kernel sequence number from
 .Pa /dev/kmsg ,