vimUtils.vimGenDocHook: fix tag generation

pkgs/misc/vim-plugins/build-vim-plugin.nix

···
     addRtp "${rtpPath}/${path}" attrs (stdenv.mkDerivation (attrs // {
       name = namePrefix + name;
 
+      # dont move the doc folder since vim expects it
+      forceShare= [ "man" "info" ];
+
       nativeBuildInputs = attrs.nativeBuildInputs or [] ++ [ vimGenDocHook ];
       inherit unpackPhase configurePhase buildPhase addonInfo preInstall postInstall;
 

pkgs/misc/vim-plugins/vim-gen-doc-hook.sh

···
 vimPluginGenTags() {
     echo "Executing vimPluginGenTags"
 
-    target="$out/@rtpPath@/$pname"
+    target="$out/@rtpPath@"
     mkdir -p $out/@rtpPath@
 
     # build help tags
···
         exit 1
         fi
     else
-        echo "No docs available"
+        echo "No docs available for $target"
     fi
 
     if [ -n "$addonInfo" ]; then