scaffolder: form data fixups

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

docs/features/software-templates/writing-custom-field-extensions.md

@@ -162,11 +162,15 @@ spec:
           ui:field: MyCustomExtension
 ```
 
-## Get data of other fields in Form from a Custom Field Extension
+## Access Data from other Fields
+
+Custom fields extensions can read data from other fields in the form via the form context. This
+is something that we discourage due to the coupling that it creates, but is sometimes still
+the most sensible solution.
 
 ```tsx
-const CustomFieldExtensionComponent(props: FieldExtensionComponentProps<string[]>) => {
-  const { formContext } = props;
+const CustomFieldExtensionComponent = (props: FieldExtensionComponentProps<string[]>) => {
+  const { formData } = props.formContext;
   ...
 };