rtnetlink.7: ffix: Remove unneeded .na / .ad tags

The result without these tags looks acceptable.
With these tags, the HTML rendering on man7.org
is bit messed up.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man7/rtnetlink.7

@@ -89,7 +89,6 @@ message, thus creating a link with the given
 .IR ifindex );
 .I ifi_change
 is reserved for future use and should be always set to 0xFFFFFFFF.
-.na
 .TS
 tab(:);
 c s s
@@ -108,7 +107,6 @@ IFLA_STATS:T{
 see below
 T}:Interface Statistics.
 .TE
-.ad
 .sp
 The value type for
 .B IFLA_STATS
@@ -210,7 +208,6 @@ struct rtmsg {
     unsigned int  rtm_flags;
 };
 .fi
-.na
 .TS
 tab(:);
 l l.
@@ -235,8 +232,6 @@ RTN_XRESOLVE:T{
 refer to an external resolver (not implemented)
 T}
 .TE
-.ad
-.na
 .TS
 tab(:);
 l l.
@@ -250,7 +245,6 @@ RTPROT_KERNEL:by the kernel
 RTPROT_BOOT:during boot
 RTPROT_STATIC:by the administrator
 .TE
-.ad
 
 Values larger than
 .B RTPROT_STATIC
@@ -263,7 +257,6 @@ for the routing daemon identifiers which are already assigned.
 
 .I rtm_scope
 is the distance to the destination:
-.na
 .TS
 tab(:);
 l l.
@@ -275,7 +268,6 @@ RT_SCOPE_LINK:route on this link
 RT_SCOPE_HOST:route on the local host
 RT_SCOPE_NOWHERE:destination doesn't exist
 .TE
-.ad
 
 The values between
 .B RT_SCOPE_UNIVERSE
@@ -286,7 +278,6 @@ are available to the user.
 The
 .I rtm_flags
 have the following meanings:
-.na
 .TS
 tab(:);
 l l.
@@ -296,7 +287,6 @@ T}
 RTM_F_CLONED:route is cloned from another route
 RTM_F_EQUALIZE:a multipath equalizer (not yet implemented)
 .TE
-.ad
 
 .I rtm_table
 specifies the routing table