docs unclear on status of constraint layout

[amueller]

https://matplotlib.org/tutorials/intermediate/constrainedlayout_guide.html

Says:

I imagine that's still the case in 3.0.2? Updating the note might make sense, then?

[jklymak]

Its been merged for a bit over a year now, so I guess we could consider making it non-experimental (if thats what you are suggesting).

[amueller]

I suggest either marking it non-experimental or marking it as still experimental. This is the docs for 3.0.2 and it only tells me what the status was in 2.2, not what the status is now.

[dstansby]

I'm happy for it to go non-experimental.

[dstansby]

(putting this as 3.0.3 as the docs should at least be fixed for 3.0.3)