fix extra char in readme cms-sanity (#14725)
fix extra char in readme cms-sanity (#14725)

Fix super minor typo in cms-sanity example readme
zeit/next.js,flybayer/next.js,flybayer/next.js,zeit/next.js,azukaru/next.js,JeromeFitz/next.js,azukaru/next.js,zeit/next.js,JeromeFitz/next.js,flybayer/next.js,JeromeFitz/next.js,flybayer/next.js,JeromeFitz/next.js,azukaru/next.js,azukaru/next.js