[Tests] lint our markdown

Author: ljharb

.travis.yml

@@ -9,11 +9,11 @@ before_install:
   - 'if [ "${TRAVIS_NODE_VERSION}" = "0.6" ]; then npm install -g [email protected] ; elif [ "${TRAVIS_NODE_VERSION}" != "0.9" ]; then case "$(npm --version)" in 1.*) npm install -g [email protected] ;; 2.*) npm install -g npm@2 ;; esac ; fi'
   - 'if [ "${TRAVIS_NODE_VERSION%${TRAVIS_NODE_VERSION#[0-9]}}" = "0" ] || [ "${TRAVIS_NODE_VERSION:0:4}" = "iojs" ]; then npm install -g [email protected] ; elif [ "${TRAVIS_NODE_VERSION}" != "0.6" ] && [ "${TRAVIS_NODE_VERSION}" != "0.9" ]; then npm install -g npm; fi'
 install:
-  - 'cd "packages/${PACKAGE}"'
+  - 'if [ -n "${PACKAGE-}" ]; then cd "packages/${PACKAGE}"; fi'
   - 'if [ "${TRAVIS_NODE_VERSION}" = "0.6" ]; then nvm install 0.8 && npm install -g [email protected] && npm install -g [email protected] && npm install -g npm@2 && npm install && nvm use "${TRAVIS_NODE_VERSION}"; else npm install; fi;'
   - 'if [ -n "${ESLINT}" ]; then npm install --no-save "eslint@${ESLINT}"; fi'
 script:
-  - 'if [ -n "${PREPUBLISH-}" ]; then npm run pretravis && npm run prepublish && npm run posttravis; else npm run travis; fi'
+  - 'if [ -n "${PREPUBLISH-}" ]; then npm run pretravis && npm run prepublish && npm run posttravis; elif [ -n "${LINT-}" ]; then npm run lint; else npm run travis; fi'
 sudo: false
 env:
   matrix:
@@ -26,6 +26,8 @@ matrix:
       env: PREPUBLISH=true ESLINT=4 PACKAGE=eslint-config-airbnb
     - node_js: "node"
       env: PREPUBLISH=true ESLINT=4 PACKAGE=eslint-config-airbnb-base
+    - node_js: "node"
+      env: LINT=true
   allow_failures:
     - node_js: "7"
     - node_js: "5"

README.md

@@ -3169,7 +3169,7 @@ Other Style Guides
     eslint: [`no-restricted-globals`](http://eslint.org/docs/rules/no-restricted-globals)
 
     > Why? The global `isNaN` coerces non-numbers to numbers, returning true for anything that coerces to NaN.
-    If this behavior is desired, make it explicit.
+    > If this behavior is desired, make it explicit.
 
     ```javascript
     // bad
@@ -3186,7 +3186,7 @@ Other Style Guides
     eslint: [`no-restricted-globals`](http://eslint.org/docs/rules/no-restricted-globals)
 
     > Why? The global `isFinite` coerces non-numbers to numbers, returning true for anything that coerces to a finite number.
-    If this behavior is desired, make it explicit.
+    > If this behavior is desired, make it explicit.
 
     ```javascript
     // bad