Add tree-sitter overrides, enable it on tests

overrides.nix

@@ -103,6 +103,13 @@ self: super: {
     ename = "so-long";
   };
 
+  tree-sitter = super.tree-sitter.overrideAttrs (esuper: {
+    postInstall = ''
+      ln -s ${super.tsc}/share/emacs/site-lisp/elpa/${super.tsc.name}/* \
+        $out/share/emacs/site-lisp/elpa/${esuper.pname}-${esuper.version}/
+    '';
+  });
+
   ts-fold = self.straightBuild {
     pname = "ts-fold";
   };

test/doom.d/init.el

@@ -104,6 +104,7 @@
        ;;taskrunner        ; taskrunner for all your projects
        ;;terraform         ; infrastructure as code
        ;;tmux              ; an API for interacting with tmux
+       tree-sitter       ; syntax and parsing, sitting in a tree...
        ;;upload            ; map local to remote projects via ssh/ftp
 
        :os
@@ -148,7 +149,8 @@
        ;;lua               ; one-based indices? one-based indices
        markdown          ; writing docs for people to ignore
        ;;nim               ; python + lisp at the speed of c
-       nix               ; I hereby declare "nix geht mehr!"
+       (nix              ; I hereby declare "nix geht mehr!"
+        +tree-sitter)
        ;;ocaml             ; an objective camel
        org               ; organize your plain life in plain text
        ;;php               ; perl's insecure younger brother