feat(tools/eaglemode): add command for opening Emacsclient

Adds a command that opens the current target in the file browser in Emacsclient.

Change-Id: Idbbec3905eb7763ce5bdc2931415db74bc5a5c31
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12367
Tested-by: BuildkiteCI
Reviewed-by: emery <emery@dmz.rs>
Reviewed-by: azahi <azat@bahawi.net>

tools/eaglemode/commands/emacsclient.nix

@@ -0,0 +1,21 @@
+{ depot, pkgs, ... }:
+
+depot.tools.eaglemode.mkCommand {
+  name = "Emacsclient";
+  hotkey = "Ctrl+E";
+
+  description = ''
+    Open target in Emacsclient.
+
+    Emacs server must be running already for this to have any effect.
+  '';
+
+  code = ''
+    ErrorIfNotSingleTarget();
+
+    my @tgt=GetTgt();
+    my $dir=$tgt[0];
+
+    ExecOrError('${pkgs.emacs}/bin/emacsclient', '-n', $dir);
+  '';
+}