refactor: Support ComponentChild(ren) in compat render/hydrate/createPortal

[rschristian]

Re: #4345

Unlikely to really matter, but every now and then we do see a user or two still using React imports in their apps for whatever reason so this'll fix their types if they're trying to render a string or whatnot.

createPortal does support ComponentChildren, that change isn't a typo.

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Unrelated, but I'll make a note to run through one day and make our use of parent & container consistent -- I noticed we use them interchangeably, which, while not an issue per se, might confuse someone new to the API.

[coveralls]

coverage: 99.605%. remained the same
when pulling 1fc799d on types/fix-hydrate-render-createPortal
into c1addc2 on main.