docs: Fix the error 404 URL on `operator/docs/prologue/quickstart.md`

[ydFu]

What this PR does / why we need it:

• Updated the hyperlink for Kubernetes kind to use the full URL (https://github.com/kubernetes-sigs/kind) for better accessibility.
• Improved the readability of instructions for testing local changes by adding clarifying punctuation and formatting adjustments.'

Which issue(s) this PR fixes: None

Special notes for your reviewer: None

Checklist

• [x] Reviewed the CONTRIBUTING.md guide (required)
• [x] Documentation added
• [] Tests updated
• [] Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• [] Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• [] If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR

[CLAassistant]

All committers have signed the CLA.