fix: add files and accordion components (#3495)

Author: devalog

fern/products/api-def/openapi-pages/overlays.mdx

@@ -51,7 +51,8 @@ actions: # Required: Ordered list of changes to apply
 Fern requires parentheses around JSONPath filter expressions. Use `[?(@.name == 'plantId')]` instead of `[?@.name == 'plantId']`.
 </Warning>
 
-### Modifying OpenAPI properties
+<AccordionGroup>
+<Accordion title="Modifying OpenAPI properties" toc={true}>
 
 Use `update` to change standard OpenAPI properties like descriptions, summaries, or other fields:
 
@@ -67,7 +68,8 @@ actions:
       description: Returns a paginated list of plants in the store inventory.
 ```
 
-### Customizing with Fern extensions
+</Accordion>
+<Accordion title="Customizing with Fern extensions" toc={true}>
 
 Use `update` to add [Fern extensions](/api-definitions/openapi/extensions/overview):
 
@@ -92,11 +94,12 @@ actions:
       x-fern-parameter-name: withDetails
 ```
 
-### Removing elements
+</Accordion>
+<Accordion title="Removing elements" toc={true}>
 
 Use `remove: true` to delete elements from your specification:
 
-```yaml title="openapi-overlays.yml"
+```yaml title="openapi-overlays.yml" {8}
 overlay: 1.0.0
 info:
   title: Remove internal endpoints
@@ -107,6 +110,9 @@ actions:
     remove: true
 ```
 
+</Accordion>
+</AccordionGroup>
+
 ## Separate overlays for SDKs and docs
 
 <Markdown src="/snippets/separate-sdks-docs.mdx" type="overlays" />

fern/snippets/different-environments.mdx

@@ -1,6 +1,6 @@
 Configure different {{type}} for production versus internal APIs:
 
-```yaml title="generators.yml"
+```yaml title="generators.yml" {5, 11}
 groups:
   production:
     specs:

fern/snippets/separate-sdks-docs.mdx

@@ -1,16 +1,19 @@
 Use different {{type}} files for SDK generation versus documentation by creating separate folders with their own `generators.yml`:
 
-```bash
-fern/
-  ├─ fern.config.json
-  ├─ openapi.yml
-  ├─ docs/
-  │   ├─ generators.yml
-  │   └─ docs-{{type}}.yml
-  └─ sdks/
-      ├─ generators.yml
-      └─ sdk-{{type}}.yml
-```
+<Files>
+  <Folder name="fern" defaultOpen>
+    <File name="fern.config.json" />
+    <File name="openapi.yml" />
+    <Folder name="docs" defaultOpen>
+      <File name="generators.yml" />
+      <File name="docs-{{type}}.yml" />
+    </Folder>
+    <Folder name="sdks" defaultOpen>
+      <File name="generators.yml" />
+      <File name="sdk-{{type}}.yml" />
+    </Folder>
+  </Folder>
+</Files>
 
 ```yaml title="sdks/generators.yml"
 api: