Add snapshot tests for method-doc

Author: kazk

jest.config.js

@@ -1,4 +1,5 @@
 module.exports = {
   // The test environment that will be used for testing
-  testEnvironment: "jest-environment-jsdom",
+  testEnvironment: 'jest-environment-jsdom',
+  snapshotSerializers: ['jest-serializer-html'],
 };

package-lock.json

@@ -37,6 +37,7 @@
     "husky": "^7.0.4",
     "jest": "^27.3.1",
     "jest-environment-jsdom": "^27.3.1",
+    "jest-serializer-html": "^7.1.0",
     "marked": "^4.0.5",
     "parcel": "^2.0.0",
     "prettier": "^2.4.1",