www: Include .so mans if found in the same package

Unfortunately, this can lead to slightly confusing scenarios, because
the exact package of the displayed man page is not very well defined.
It's possible that, when browsing from a package listing to a man page,
you may see an included file that does not come from the package you
browsed from.
E.g. https://manned.org/pwrite/5f2909f6 - that man page simply includes
pread.2, but from the URL it's unclear from which package or system it
should be included.

The only way to fix this is to add the package ID to the link format.

lib/ManUtils/ManUtils.pm

@@ -24,14 +24,6 @@ sub fmt {
   $$output = '';
   @$errors = ();
 
-  # tix comes with[1] a custom(?) macro package. But it looks okay even without
-  # loading that.
-  # [1] It actually doesn't, the tcllib package appears to have that file, but
-  # doesn't '.so' it.
-  $input =~ s/^\.so man.macros$//mg;
-  # Other .so's should be handled by html()
-  $input =~ s/^\.so (.+)$/.in -10\n.sp\n\[\[\[MANNEDINCLUDE$1\]\]\]/mg;
-
   $input =
     # Disable hyphenation, since that screws up man page references. :-(
      ".hy 0\n.de hy\n..\n"