Demonstrate markdown lint errors

[joshka]

• docs: lint and reformat the main markdown files
• style: automatically format ci.yaml
• docs: ensure tokio readme is identical to root readme
• docs: introduce intentional errors to readme to demonstrate lint action

Motivation

Test the markdown lint action introduced in #6480

Solution

Adds a few intentional errors to the README to show how these will be surfaced by the markdown lint action