docs: Add documentation for x-fern-ignore at property level

fern/products/api-def/openapi-pages/extensions/ignore.mdx

@@ -1,9 +1,9 @@
 ---
-title: Ignoring schemas or endpoints
-description: Skip reading endpoints or schemas using the `x-fern-ignore` extension
+title: Ignoring elements
+description: Skip reading endpoints, schemas, or properties using the `x-fern-ignore` extension
 ---
 
-If you want Fern to skip reading any endpoints or schemas, use the `x-fern-ignore` extension.
+If you want Fern to skip reading any endpoints, schemas, or properties, use the `x-fern-ignore` extension.
 
 To skip an endpoint, add `x-fern-ignore: true` at the operation level.
 
@@ -24,3 +24,18 @@ components:
       x-fern-ignore: true
       ...
 ```
+
+To skip a property within a schema, add `x-fern-ignore: true` at the property level.
+
+```yaml title="x-fern-ignore at property level in openapi.yml" {9}
+components:
+  schemas:
+    User:
+      type: object
+      properties:
+        name:
+          type: string
+        internalField:
+          x-fern-ignore: true
+          type: string
+```