emacsWithPackages: do not symlink $emacs/share/emacs

I see no reason to symlink this dir.

Doing so may shadow unwanted libraries since the site-start.el of
Emacs adds paths under NIX_PROFILES to load-path.

It is added in [1] to fix "building emacs".  However, I have no issue
in building and using Emacs after removing it.

[1]: https://github.com/NixOS/nixpkgs/pull/89351

pkgs/build-support/emacs/wrapper.nix

@@ -224,7 +224,7 @@ runCommand
 
     mkdir -p $out/share
     # Link icons and desktop files into place
-    for dir in applications icons info man emacs; do
+    for dir in applications icons info man; do
       ln -s $emacs/share/$dir $out/share/$dir
     done
   ''