Establish standards for documentation

[nrobinson2000]

Hey everyone,

Not sure if this has been brought up already, but I recently noticed a lot of inconsistencies throughout the documentation.

• The style of descriptions for return values for library methods.
• Many of the code snippets are using ```C++ instead of ```cpp.
• Indentation style for code snippets.
• Object construction style.

I think it would be a good idea to create a style guide for the documentation so that the formatting style for the descriptions of methods can be consistent throughout the documentation, improving readability and accessibility to information.

I recognize that reformatting the documentation will take lots of effort but I think that it is in everyone's best interest to improve the documentation however possible.

I recently opened a pull request that makes some of the changes listed above, but it is nowhere close to addressing the entire documentation: https://github.com/particle-iot/docs/pull/1024