[fixed]: css class added to root document instead of modal ownerDocument

[leoc4e]

Fixes #[964]
I am trying to open the modal inside an iframe, but the bodyOpenClassName would be applied to the rootDocument instead.
I would like to use the parentSelector to determine where the bodyOpenClassName should be added instead of just using document.body

Changes proposed:

• htmlOpenClassName add to the modal ownerDocument html instead
• bodyOpenClassName add to the modal ownerDocument body instead
• Update doc

Upgrade Path (for changed or removed APIs):

Acceptance Checklist:

• The commit message follows the guidelines in CONTRIBUTING.md.
• Documentation (README.md) and examples have been updated as needed.
• If this is a code change, a spec testing the functionality has been added.
• If the commit message has [changed] or [removed], there is an upgrade path above.

[diasbruno]

LEGIT.

[leoc4e]

@diasbruno
Is there anything I should do for this PR to move forward?

[diasbruno]

I didn't have time to look at it, but one thing is I don't know how old is ownerDocument. If you can have look on it to see if it is safe to use, then ok...

[leoc4e]

I think it should be safe to use,

https://developer.mozilla.org/en-US/docs/Web/API/Node/ownerDocument
https://caniuse.com/?search=ownerDocument
it is supported even for IE 6 in 2002
for android it is not supported until 4.4 (2014)

And since I am using (parentSelector && parentSelector().ownerDocument) || document
it should fallback to use the document if ownerDocument is undefined/null🤞

[diasbruno]

Great. Thanks for the PR e bom trabalho!