fix(3p/overlays): Use notmuch.el from nixpkgs

...  instead of the one from the overlay, which can be out of sync.

This requires the TVL overlay to be applied after the Emacs overlay.

Change-Id: Idac403ea612e334c14b45759dc216699a506678f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3484
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <mail@tazj.in>

third_party/nixpkgs/default.nix

@@ -63,9 +63,9 @@ in import nixpkgsSrc {
   overlays = [
     commitsOverlay
     stableOverlay
-    depot.third_party.overlays.tvl
     depot.third_party.overlays.haskell
     depot.third_party.overlays.emacs
+    depot.third_party.overlays.tvl
     depot.third_party.overlays.ecl-static
   ];
 }

third_party/overlays/tvl.nix

@@ -26,6 +26,10 @@ self: super: {
   emacsPackagesFor = emacs: (
     (super.emacsPackagesFor emacs).overrideScope' (eself: esuper: {
       tvlPackages = depot.tools.emacs-pkgs // depot.third_party.emacs;
+
+      # Use the notmuch from nixpkgs instead of from the Emacs
+      # overlay, to avoid versions being out of sync.
+      notmuch = super.notmuch.emacs;
     })
   );