docs: update readme

[chalkygames123]

• Fix broken images
• Use relative URL for internal references
• Match sample.png image description to the core's readme
• Rename sample.png to screenshot.png
• Remove redundant title from images
• Stop using redundant link reference definitions
• Match "What?" section content to the core's readme with grammatical corrections
• Fix installation commands
• Match "Usage" section content to the core's readme
• Match "Support" section content to the core's readme

[github-actions[bot]]

:tada: This PR is included in version 1.5.0 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: