Docs: Dogfood plugin by linting readme (#145)

.eslintrc.js

@@ -22,6 +22,13 @@ module.exports = {
         PACKAGE_NAME
     ],
 
+    "overrides": [
+        {
+            "files": ["*.md"],
+            "processor": "markdown/markdown"
+        }
+    ],
+
     "env": {
         "node": true
     },

README.md

@@ -172,6 +172,9 @@ for code snippets. It also points to the fact that some rules
 one may wish for documentation to be more liberal in providing padding for
 readability.
 
+<!-- This is actually JSON, but using JS lets it include comments. -->
+<!-- eslint-skip -->
+
 ```js
 // .eslintrc.json
 {
@@ -192,6 +195,9 @@ readability.
 
 The `strict` rule is technically satisfiable inside of Markdown code blocks, but writing a `"use strict"` directive at the top of every code block is tedious and distracting. We recommend a glob pattern for `.md` files to disable `strict` and enable the `impliedStrict` [parser option](https://eslint.org/docs/user-guide/configuring#specifying-parser-options) so the code blocks still parse in strict mode:
 
+<!-- This is actually JSON, but using JS lets it include comments. -->
+<!-- eslint-skip -->
+
 ```js
 // .eslintrc.json
 {

package.json

@@ -20,7 +20,7 @@
     "linter"
   ],
   "scripts": {
-    "lint": "eslint .",
+    "lint": "eslint --ext js,md .",
     "test": "npm run lint && npm run test-cov",
     "test-cov": "nyc _mocha -- -c tests/lib/**/*.js",
     "generate-release": "eslint-generate-release",