Guide: setting up a multi-language format-on-save with Prettier

I see too many devs running separate formatters for each language. It's messy. Prettier can handle most of it if you configure it right.

You need the core plugin plus language-specific add-ons. Here's a working `.prettierrc` for JS/TS, JSON, YAML, and Markdown.

```json
{
"trailingComma": "es5",
"tabWidth": 2,
"semi": true,
"singleQuote": true,
"plugins": [
"@prettier/plugin-xml",
"prettier-plugin-sql",
"prettier-plugin-tailwindcss"
]
}
```

Key setup steps:
* Install `prettier` and all required plugins in devDependencies.
* Enable "Format On Save" in your editor.
* Ensure your editor's Prettier extension uses the project's local version.

For languages like Go or Python, Prettier isn't the right tool. Use gofmt/black directly via editor hooks instead of forcing it.