fix: Search backward and forward for leaf nodes in non contenteditable elements

[delijah]

Description
This PR change the toSlatePoint function in a way, that if the selection is within a contentEditable={false} node, it will search backward and forward for valid slate leafs. Before it was only looking backward by default.

Issue
Fixes: #5932

Example
You can find a GIF and a codesandbox link in the linked issue. Here you can see how it behaves after the fix:

Context
I am aware, that this is a very sensible spot to make changes. Help appreciated!

Checks

• The new code matches the existing patterns and styles.
• The tests pass with yarn test.
• The linter passes with yarn lint. (Fix errors with yarn fix.)
• The relevant examples still work. (Run examples with yarn start.)
• You've added a changeset if changing functionality. (Add one with yarn changeset add.)

[changeset-bot]

🦋 Changeset detected

Latest commit: 835b1d8

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

This PR includes changesets to release 1 package

Name	Type
slate-dom	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[delijah]

How shall we proceed here @12joan ?

[12joan]

How shall we proceed here @12joan ?

Apologies if I gave you the wrong impression in the other threads where we've talked, but I'm not actually a Slate maintainer. I just comment on issues and PRs from time to time when I feel my input could be helpful. 😃

@dylans is the maintainer of Slate, and will likely review this PR in due course.

[delijah]

Apologies if I gave you the wrong impression in the other threads where we've talked, but I'm not actually a Slate maintainer. I just comment on issues and PRs from time to time when I feel my input could be helpful. 😃

I am sorry, there was probably some desperation involved, tagging you 🙈 Thx for the reply though @12joan and thx for proceeding @dylans !