use prettier and github action to normalize markdown document syntax

[jimexist]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
(This section helps Arrow developers understand the context and why for this feature, in addition to the what)

use prettier and github action to normalize markdown document syntax

Describe the solution you'd like
A clear and concise description of what you want to happen.

use prettier and github action to normalize markdown document syntax

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.