Add "Select to Next / Previous Bookmark" commands

[alefragnani]

Requirements

• Filling out the template is required. Any pull request that does not include enough information to be reviewed in a timely manner may be closed at the maintainers' discretion.
• All new code requires tests to ensure against regressions

Description of the Change

This PR adds two new commands to the package, Select to Next Bookmark and Select to Previous Bookmark, which creates a selection range from the cursor position to the next/previous bookmark.

Alternate Designs

It is a simple design, because the command is simple. Just using the already provided setSelectedBufferRange function to create the selection.

Benefits

You can take advantage of bookmarks to also select areas that you intend to Copy/Replace text.

Possible Drawbacks

Nothing at all, since nothing has changed in the already existing code. The two new commands are isolated.

Applicable Issues

This PR Closes #24 .

[BinaryMuse]

Thanks so much for the contribution!