procfs(5) is not required by ps(1) and w(1) anymore

Remove references of those tools in procfs(5)

share/man/man5/procfs.5

@@ -2,7 +2,7 @@
 .\" Written by Garrett Wollman
 .\" This file is in the public domain.
 .\"
-.Dd April 22, 2013
+.Dd December 26, 2015
 .Dt PROCFS 5
 .Os
 .Sh NAME
@@ -17,11 +17,7 @@ The process file system, or
 .Nm ,
 implements a view of the system process table inside the file system.
 It is normally mounted on
-.Pa /proc ,
-and is required for the complete operation of programs such as
-.Xr ps 1
-and
-.Xr w 1 .
+.Pa /proc .
 .Pp
 The
 .Nm