fix(tazjin/emacs): add dwebp to Emacs' $PATH

Change-Id: I20723b7d98a24e3f06810f0a0ede8a05c80156a8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/4405
Reviewed-by: tazjin <mail@tazj.in>
Autosubmit: tazjin <mail@tazj.in>
Tested-by: BuildkiteCI

users/tazjin/emacs/default.nix

@@ -18,7 +18,10 @@ let
   currentTelega = epkgs: epkgs.melpaPackages.telega;
 
   # $PATH for binaries that need to be available to Emacs
-  emacsBinPath = lib.makeBinPath [ (currentTelega pkgs.emacsPackages) ];
+  emacsBinPath = lib.makeBinPath [
+    (currentTelega pkgs.emacsPackages)
+    pkgs.libwebp # for dwebp, required by telega
+  ];
 
   identity = x: x;