[WIP] Cookbook grammar and style fixes

This is a follow-up for #4679 

It Fixes some general issues in grammar, style and readability.

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | >= 2.3
| Fixed tickets | 
Thought this is a subordinate clause: http://www.chompchomp.com/terms/subordinateclause.htm