kanshi: allow multiple exec statements per profile

kanshi configurations can have more than one exec statement in a
profile. This change allows services.kanshi.profiles.<name>.exec to be
a list of strings rather than a single string.

modules/services/kanshi.nix

@@ -104,23 +104,26 @@ let
       };
 
       exec = mkOption {
-        type = types.nullOr types.str;
-        default = null;
+        type = with types; coercedTo str singleton (listOf str);
+        default = [ ];
         example =
-          "\${pkg.sway}/bin/swaymsg workspace 1, move workspace to eDP-1";
+          "[ \${pkg.sway}/bin/swaymsg workspace 1, move workspace to eDP-1 ]";
         description = ''
-          Command executed after the profile is succesfully applied.
+          Commands executed after the profile is succesfully applied.
+          Note that if you provide multiple commands, they will be
+          executed asynchronously with no guaranteed ordering.
         '';
       };
     };
   };
 
   profileStr = name:
-    { outputs, exec, ... }:
-    ''
+    { outputs, exec, ... }: ''
       profile ${name} {
-        ${concatStringsSep "\n  " (map outputStr outputs)}
-    '' + optionalString (exec != null) "  exec ${exec}\n" + ''
+        ${
+          concatStringsSep "\n  "
+          (map outputStr outputs ++ map (cmd: "exec ${cmd}") exec)
+        }
       }
     '';
 in {

tests/modules/services/kanshi/basic-configuration.conf

@@ -1,8 +1,14 @@
+profile backwardsCompat {
+  output "LVDS-1" enable
+  exec echo "7 eight 9"
+}
+
 profile desktop {
   output "eDP-1" disable
   output "Iiyama North America PLE2483H-DP" enable position 0,0
   output "Iiyama North America PLE2483H-DP 1158765348486" enable mode 1920x1080 position 1920,0 scale 2.100000 transform flipped-270
   exec echo "1 two 3"
+  exec echo "4 five 6"
 }
 
 profile nomad {

tests/modules/services/kanshi/basic-configuration.nix

@@ -11,7 +11,7 @@
           }];
         };
         desktop = {
-          exec = ''echo "1 two 3"'';
+          exec = [ ''echo "1 two 3"'' ''echo "4 five 6"'' ];
           outputs = [
             {
               criteria = "eDP-1";
@@ -32,6 +32,13 @@
             }
           ];
         };
+        backwardsCompat = {
+          outputs = [{
+            criteria = "LVDS-1";
+            status = "enable";
+          }];
+          exec = ''echo "7 eight 9"'';
+        };
       };
       extraConfig = ''
         profile test {