(conan-io#20688) Update meson template package

* Add comments and show how to disable all features by default

* Use a lambda

docs/package_templates/meson_package/all/conanfile.py

@@ -107,12 +107,18 @@ def source(self):
         get(self, **self.conan_data["sources"][self.version], strip_root=True)
 
     def generate(self):
+        # Meson feature options must be set to "enabled" or "disabled"
+        feature = lambda option: "enabled" if option else "disabled"
+
         # default_library and b_staticpic are automatically parsed when self.options.shared and self.options.fpic exist
         # buildtype is automatically parsed for self.settings
         tc = MesonToolchain(self)
         # In case need to pass definitions directly to the compiler
         tc.preprocessor_definitions["MYDEFINE"] = "MYDEF_VALUE"
-        tc.project_options["feature"] = "enabled" if self.options.get_safe("feature") else "disabled"
+        # Meson features are typically enabled automatically when possible.
+        # The default behavior can be changed to disable all features by setting "auto_features" to "disabled".
+        tc.project_options["auto_features"] = "disabled"
+        tc.project_options["feature"] = feature(self.options.get_safe("feature"))
         # Meson project options may vary their types
         tc.project_options["tests"] = False
         tc.generate()