Docs for merged query defaults

[matt-tingen]

I just updated my app from v4 to v5 and was looking to take advantage of the cascading query defaults (discussion, PR). In doing so, I noticed there seems to be a couple of issues in the docs:

• The API docs for getQueryDefaults/setQueryDefaults still reflect the v4 behavior
• The migration guide makes no mention of the changed behavior

I'd like to make a PR to update the docs, but wanted clarify a couple things:

• The v5 merging behavior is intended to be part of the public API, correct?
• The v4 behavior was documented but having multiple matching defaults was strongly discouraged by a console.error. Because of this, there's arguments to be made both ways as to whether multiple matches were supported in v4 or not. Given this, is the v5 behavior a breaking change or a feature?

[TkDodo]

yeah you’re right. I think we changed it but forgot updating the docs. The v5 update was a breaking change I believe.