* Examples: clarify language around Yarn create & npx
* add missing READMEs and create-next-app usage
* suggest people tag jthegedus in firebase related issues
* add yarn alt instructions
* cerebraljs example readme & fixes
* remove global npm install of create-next-app
* add npx to create-next-app command in examples
* add bash to shell snippets
* add yarn create to next-app command in examples
* fix READMEs named with lowercase
* change READMEs to use UPPERCASE
* Add details to custom Document documentation
Custom document must be created at ./Pages/_document.js, which is not
noted in the README… so I updated it.
* Add note to styled-components example about existing issue
* Made phrasing a bit more clear
* Another phrasing update.
* from P to p