fix: marks at the start of the selection

[WindRunnerMax]

Description
When the selection is at the end of the previous node, using Editor.marks retrieves the marks of the previous node. In this case, calling Editor.addMark does not override the previous node, thus causing the states to be out of sync.

Issue
Fixes: #5724

Example

Before the fix:

When fixed:

Context

Thanks to the fix in #5580 , we can easily address this issue. By swapping the positions of anchor and focus according to Range.isBackward, we can then proceed with the original correction logic.

Additionally, since Editor.nodes calls Range.edges to recalibrate the order of anchor and focus, it won't affect the original Editor.marks logic.

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: 6e46989

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

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