test: don't lint autogenerated test/addons/doc-*/

The JS source files in test/addons/doc-*/ are scraped from the reference
documentation in doc/api and need not conform to the style guide.

PR-URL: nodejs/node#1793
Reviewed-By: Trevor Norris <[email protected]>

Author: bnoordhuis

.eslintignore

@@ -1,4 +1,5 @@
 lib/punycode.js
+test/addons/doc-*/
 test/fixtures
 test/**/node_modules
 test/parallel/test-fs-non-number-arguments-throw.js