Expand schema directive Tip on generators.yml reference page

[fern-api]

Updated the <Tip> callout near the top of fern/products/sdks/reference/generators-yml-reference.mdx to explain which editors support the yaml-language-server schema directive. The expanded tip now names VS Code (with a link to the YAML extension), Neovim, Emacs, and other YAML Language Server–powered editors, and adds a note for IntelliJ IDEA users explaining that IntelliJ doesn't read the directive natively and directing them to configure schema validation via Settings → Languages & Frameworks → Schemas and DTDs → JSON Schema Mappings. The existing code block showing the directive is unchanged.

[github-actions]

📝 [vale] <FernStyles.Acronyms> _{reported by reviewdog 🐶}
'IDEA' has no definition.

[github-actions]

🚫 [vale] <Microsoft.Contractions> _{reported by reviewdog 🐶}
Use 'doesn't' instead of 'does not'.

Suggested change

To enable intelligent YAML validation and autocompletion in your editor, add a schema directive to the top of your `generators.yml` file. This directive is recognized by the [YAML Language Server](https://github.com/redhat-developer/yaml-language-server), which powers YAML support in **VS Code** (via the [YAML extension](https://marketplace.visualstudio.com/items?itemName=redhat.vscode-yaml)), **Neovim**, **Emacs**, and other editors that integrate the YAML Language Server. **IntelliJ IDEA** uses its own built-in YAML support and does not read the `yaml-language-server` directive natively; for schema validation in IntelliJ, configure the schema mapping in **Settings → Languages & Frameworks → Schemas and DTDs → JSON Schema Mappings** and point it to `https://schema.buildwithfern.dev/generators-yml.json`.

To enable intelligent YAML validation and autocompletion in your editor, add a schema directive to the top of your `generators.yml` file. This directive is recognized by the [YAML Language Server](https://github.com/redhat-developer/yaml-language-server), which powers YAML support in **VS Code** (via the [YAML extension](https://marketplace.visualstudio.com/items?itemName=redhat.vscode-yaml)), **Neovim**, **Emacs**, and other editors that integrate the YAML Language Server. **IntelliJ IDEA** uses its own built-in YAML support and doesn't read the `yaml-language-server` directive natively; for schema validation in IntelliJ, configure the schema mapping in **Settings → Languages & Frameworks → Schemas and DTDs → JSON Schema Mappings** and point it to `https://schema.buildwithfern.dev/generators-yml.json`.

[github-actions]

🌿 Preview your docs: https://fern-preview-2026-09-02-fern-ai-d8be69-aec066dc.docs.buildwithfern.com/learn

Here are the markdown pages you've updated:

• learn/sdks/reference/generators-yml