Docs [Block Editor Handbook / Getting Started / Block Development Environment]: Fix links

[juanmaguitar]

What?

Fix a few links in Block Editor Handbook / Getting Started / Block Development Environment
It also includes a missing callout CSS class that was causing callout styles not to display correctly.

Why?

To ensure a nice learning and discovering experience

[t-hamano]

Thanks for the PR 🙌

How about fixing the anchor (#nodejs-development-tools) of this line as well?

gutenberg/docs/getting-started/devenv/get-started-with-wp-now.md

Line 5 in 9fa8d8d

Before following this guide, install [Node.js development tools](/docs/getting-started/devenv#nodejs-development-tools) if you have not already done so. It's recommended that you use the latest version of `node`. `wp-now` requires at least `node` v18 and v20 if you intend to use its [Blueprints](https://github.com/WordPress/playground-tools/tree/trunk/packages/wp-now#using-blueprints) feature.

[t-hamano]

Suggested change

When developing for the Block Editor, you will need [Node.js](https://nodejs.org/en) development tools along with a code editor and a local WordPress environment (see [Block Development Environment](/docs/getting-started/devenv/)). Node.js (`node`) is an open-source runtime environment that allows you to execute JavaScript code from the terminal (also known as a command-line interface, CLI, or shell)

When developing for the Block Editor, you will need [Node.js](https://nodejs.org/en) development tools along with a code editor and a local WordPress environment (see [Block Development Environment](/docs/getting-started/devenv/README.md)). Node.js (`node`) is an open-source runtime environment that allows you to execute JavaScript code from the terminal (also known as a command-line interface, CLI, or shell)

Looking at the other links in the docs directory, it looks like we need to explicitly specify the file name.

[juanmaguitar]

Thanks a lot for your suggestions @t-hamano 🙏
I have included your suggestions in this PR

[github-actions]

Flaky tests detected in 1f3bccc.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/6235149289
📝 Reported issues:

• [Flaky Test] should partially select with shift + click (@webkit) #53524 in /test/e2e/specs/editor/various/multi-block-selection.spec.js

[t-hamano]

LGTM 🚀