Documentation: Flowcharts styling not fully documented

[PackElend]

see mentions the option messageAlign: left but that cannot be found in https://github.com/mermaid-js/mermaid/blob/develop/src/docs/flowchart.md#styling-and-classes.
Could anyone, who knows the options update the documentation

MERCI :)

[sidharthv96]

This problem is bigger than flowcharts and affects almost all types.
We're planning on tackling it from the root, trying to generate documentation from the code.

#3416

[jgreywolf]

Closing in favor of #3416