docExpansion add one more option

[faithfulman18]

Would you consider adding one more option for the docExpansion

Currently there are these settings:

None
List
Full

I wish there was also 'First'

'First', would just open the first tag in the list. With some of our API's getting larger, I like the ability to have it collapsed, but it's nice to be able to see the first tag section open on load. In our case it is our Authentication Section which is first and works well to be first.

?

Thanks!