nixos/modules: remove trailing whitespace

This leads to ci failure otherwise if the file gets changed.
git-blame can ignore whitespace changes.

nixos/modules/services/web-apps/pgpkeyserver-lite.nix

@@ -33,7 +33,7 @@ in
         description = "
           Which hostname to set the vHost to that is proxying to sks.
         ";
-      };     
+      };
 
       hkpAddress = mkOption {
         default = builtins.head sksCfg.hkpAddress;