add more documentation to api doc

1 job from master in 10 seconds (queued for 5 seconds)
Status Job ID Name Coverage
failed #314


Name Stage Failure
pages Pages There is an unknown failure, please try again
npm ERR! You can get information on how to open an issue for this project with:
npm ERR! npm bugs html-custom-elements
npm ERR! Or if that isn't available, you can get their info via:
npm ERR! npm owner ls html-custom-elements
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR! /builds/JadeProListening/html-custom-elements/npm-debug.log
ERROR: Build failed: exit code 1