bacon: add module

Bacon is a background rust code checker. See
<https://dystroy.org/bacon/>.

tests/modules/programs/bacon/bacon.nix

@@ -0,0 +1,23 @@
+{ ... }: {
+  programs.bacon = {
+    enable = true;
+    settings = {
+      jobs = {
+        ta = {
+          command = [ "cargo" "test" "--all-features" "--color" "always" ];
+          need_stdout = true;
+        };
+      };
+      export = {
+        enabled = true;
+        path = ".bacon-locations";
+        line_format = "{kind} {path}:{line}:{column} {message}";
+      };
+    };
+  };
+  test.stubs.bacon = { };
+  nmt.script = ''
+    assertFileExists home-files/.config/bacon/prefs.toml
+    assertFileContent home-files/.config/bacon/prefs.toml ${./expected.toml}
+  '';
+}

tests/modules/programs/bacon/default.nix

@@ -0,0 +1 @@
+{ bacon-program = ./bacon.nix; }

tests/modules/programs/bacon/expected.toml

@@ -0,0 +1,8 @@
+[export]
+enabled = true
+line_format = "{kind} {path}:{line}:{column} {message}"
+path = ".bacon-locations"
+
+[jobs.ta]
+command = ["cargo", "test", "--all-features", "--color", "always"]
+need_stdout = true