Update SwiftLint to version 0.56.1

[defagos]

Description

This PR updates SwiftLint 0.56.1 and tweaks a few rules accordingly.

Changes made

• Update SwiftLint.
• Enable prefer_key_path and perform associated code adjustments.
• Disable no_empty_block and contrasted_opening_brace explicitly.

Minor (unrelated) documentation improvements have been made as well:

• Fix typo in documentation.
• Add feedback number.

Checklist

• [x] APIs have been properly documented (if relevant).
• [x] The documentation has been updated (if relevant).
• [x] New unit tests have been written (if relevant).
• [x] The demo has been updated (if relevant).