Add MapEntries control flow component.

[AlexErrant]

This PR adds <MapEntries>, which is a small iteration on <Entries>. A character-level diff may be useful when reviewing this PR, as most of my changes were copy/paste/modify. E.g. https://www.diffchecker.com/zRdYuasY/ (note the "Highlight change", "Character" option on the left side. (That link expires in a month - there is no permanent option.))

I also add a demo for <Entries>, <MapEntries>, and ReactiveMap working with <MapEntries>, which accounts for most of the linecount. Here's a video of the <MapEntries> demo showing how it's fine-grained.

chrome_F9oHokxTNJ.mp4

If this gets accepted I'll also contribute <SetEntries> in a followup.

[changeset-bot]

🦋 Changeset detected

Latest commit: 533c821

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@solid-primitives/keyed	Minor
@solid-primitives/immutable	Patch

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[thetarnav]

All good but this should be added to the map package directly.

[thetarnav]

Ok
my bad with the initial suggestion, I haven't looked too deeply at the changes and assumed that MapEntries directly depends on the map package
I think that MapEntries should be added to keyed package like it was at the beginning (you can just revert I guess)
The demo shows both the usage with Map and ReactiveMap which is great
But the docs should mention it as well, explain when you'd use one or another, how does that impact rendering
Also some basic tests are missing
It would be useful to ensure that the interaction between Map, ReactiveMap and MapEntries is covered by the tests and doesn't change.

[thetarnav]

MapEntries doesn't have any special interaction with ReactiveMap, right?
The demo works the same way for both.
If there is no difference then it might be pointless to even include ReactiveMap there nor add any special tests.

[thetarnav]

this month passed fast

[AlexErrant]

I think that MapEntries should be added to keyed package like it was at the beginning

Some food for bikeshedding (I really do not care, just bringing it up cuz why not), as of 9ebe450 , <Entries> no longer uses keyArray. Nor does <MapEntries>, so one could argue that they don't belong in keyed. Maybe Entries, MapEntries, and SetEntries should be their own package/primitive? Or part of List?

this month passed fast

Ah, I probably pasted the wrong link; updated the post >_>

[thetarnav]

Let's stick with keyed right now.
Can be moved to a different package if needed later.