pet: fix settings format issue

Before it was not possible to place setting values outside the
`General` section.

tests/modules/programs/pet/default.nix

@@ -1 +1,5 @@
-{ pet-snippets = ./snippets.nix; }
+{
+  pet-snippets = ./snippets.nix;
+  pet-settings_21_05 = ./settings_21_05.nix;
+  pet-settings_21_11 = ./settings_21_11.nix;
+}

tests/modules/programs/pet/settings_21_05.nix

@@ -0,0 +1,26 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+{
+  home.stateVersion = "21.05";
+  programs.pet = {
+    enable = true;
+    selectcmdPackage = config.lib.test.mkStubPackage { };
+    settings.editor = "nvim";
+  };
+
+  test.stubs.pet = { };
+
+  nmt.script = ''
+    assertFileContent home-files/.config/pet/config.toml \
+      ${
+        builtins.toFile "pet-settings.toml" ''
+          [General]
+          editor = "nvim"
+          selectcmd = "fzf"
+          snippetfile = "/home/hm-user/.config/pet/snippet.toml"
+        ''
+      }
+  '';
+}

tests/modules/programs/pet/settings_21_11.nix

@@ -0,0 +1,42 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+{
+  home.stateVersion = "21.11";
+  programs.pet = {
+    enable = true;
+    selectcmdPackage = config.lib.test.mkStubPackage { };
+    settings = {
+      General = {
+        backend = "Gitlab";
+        editor = "nvim";
+      };
+      Gitlab = {
+        access_token = "1234";
+        file_name = "pet-snippets.toml";
+        visibility = "public";
+      };
+    };
+  };
+
+  test.stubs.pet = { };
+
+  nmt.script = ''
+    assertFileContent home-files/.config/pet/config.toml \
+      ${
+        builtins.toFile "pet-settings.toml" ''
+          [General]
+          backend = "Gitlab"
+          editor = "nvim"
+          selectcmd = "fzf"
+          snippetfile = "/home/hm-user/.config/pet/snippet.toml"
+
+          [Gitlab]
+          access_token = "1234"
+          file_name = "pet-snippets.toml"
+          visibility = "public"
+        ''
+      }
+  '';
+}