Improve editor's behavior while dataset altering

[budnix]

Context

The PR improves the editor's behavior in cases when the dataset is changed. The PR improves the following cases:

Update the editor position when the row (or column) is added above the cell

The editor is shifted down, and it's still opened and ready to continue typing the value. After approving the changes by hitting the Enter key, the value is applied to the correct cell.

Update the editor position when the row (or column) is removed above the cell

The editor is shifted up, and it's still opened and ready to continue typing the value. After approving the changes by hitting the Enter key, the value is applied to the correct cell.

Close the editor and revoke its value when the cell is deleted

Additionally, the PR improves the selection shift algorithm, which updates the selection position after removing or adding rows/columns.

How has this been tested?

I tested the changes locally, and I covered the feature with new tests.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Related issue(s):

1. fixes https://github.com/handsontable/dev-handsontable/issues/805

Affected project(s):

• handsontable

Checklist:

• I have reviewed the guidelines about Contributing to Handsontable and I confirm that my code follows the code style of this project.
• I have signed the Contributor License Agreement

[github-actions]

Launch the local version of documentation by running:

npm run docs:review b6e2ef11d2190629c88bbe898d17fad02aa38947