chore(docs): use proper Jamstack casing (#13697)
chore(docs): use proper Jamstack casing (#13697)

`JAMstack` is now `Jamstack`.
zeit/next.js,flybayer/next.js,flybayer/next.js,azukaru/next.js,azukaru/next.js,flybayer/next.js,JeromeFitz/next.js,azukaru/next.js,JeromeFitz/next.js,zeit/next.js,flybayer/next.js,zeit/next.js,JeromeFitz/next.js,azukaru/next.js,JeromeFitz/next.js