README: fix entrypoint doc
README: fix entrypoint doc

README: better entrypoint wording

dlorenc/nodejs-docker,dlorenc/nodejs-docker,Twnel/nodejs-docker,mindhog/nodejs-docker,ReadyTalk/nodejs-docker,GoogleCloudPlatform/nodejs-docker,GoogleCloudPlatform/nodejs-docker,dlorenc/nodejs-docker,ofrobots/nodejs-docker,GoogleCloudPlatform/nodejs-docker,Twnel/nodejs-docker