Fix copy-paste error in the RadioButtonInput docs

Author: connor-baer

packages/circuit-ui/components/RadioButtonGroup/RadioButtonInput.mdx

@@ -7,7 +7,7 @@ import * as Stories from './RadioButtonInput.stories';
 
 <Status variant="internal" />
 
-This is a low-level component for advanced use cases. Only use it if the [CheckboxGroup](Forms/RadioButtonGroup/Docs) components don't meet your requirements.
+This is a low-level component for advanced use cases. Only use it if the [RadioButtonGroup](Forms/RadioButtonGroup/Docs) component doesn't meet your requirements.
 
 <Story of={Stories.Base} />
 <Props />