man: get rid of useless reference to GNU style options

No need to state the obvious here.

man/man8/lnstat.8

@@ -13,8 +13,6 @@ command.
 In addition to routing cache statistics, it supports any kind of statistics the linux kernel
 exports via a file in /proc/net/stat/.
 .SH OPTIONS
-These programs follow the usual GNU command line syntax, with long
-options starting with two dashes (`-').
 lnstat supports the following options.
 .TP
 .B \-h, \-\-help

man/man8/ss.8

@@ -14,10 +14,6 @@ It can display more TCP and state informations than other tools.
 .SH OPTIONS
 When no option is used ss displays a list of 
 open non-listening TCP sockets that have established connection.
-.P
-These programs follow the usual GNU command line syntax, with long
-options starting with two dashes (`-').
-A summary of options is included below.
 .TP
 .B \-h, \-\-help
 Show summary of options.