feat(users/sterni): move clhs.clhs-lookup to clhs-lookup

This way ci should pick up on clhs-lookup since only a single derivation
is exposed with the default.nix and it is less cumbersome to type the
attribute path (users.sterni.clhs.clhs-lookup →
users.sterni.clhs-lookup). The exposed CLHS wasn't used for anything
anyways and I can always expose it again using passthru or extra if it's
ever merged.

Change-Id: I6c5aeba1b58ca650700c6efa0913e4b42685ea6b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2461
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>

users/sterni/clhs-lookup/default.nix

@@ -32,6 +32,5 @@ let
       ./clhs-lookup.lisp
     ];
   };
-in {
-  inherit clhs clhs-lookup;
-}
+in
+  clhs-lookup