DOC: Single Document For Code Guidelines
#### Location of the documentation

https://pandas.pydata.org/docs/development/code_style.html
https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#code-standards

#### Documentation problem

Most of the documentation for the coding style guidelines is limited and in multiple locations. Much of the coding style is in a script.

#### Suggested fix for documentation

I propose to create a single document that contains all the coding guidelines.
This will allow new contributors to easily see all the required syntax and style for the project.
This also allows newer users to not have to guess against a script or have to keep submitting code over and over to find mistakes.
