docs: Render type parameters in external SymbolDoc symbols

The external `SymbolDoc` type did not render type parameters:

```ts
Record<string, number>
```

This fix updates the external symbol type to include the type parameters.

modules/docs/lib/widgets/external.tsx

@@ -1,10 +1,14 @@
 import React from 'react';
 import {ExternalHyperlink} from '@workday/canvas-kit-react/button';
 
+import {renderTypeParameters} from '../widgetUtils';
 import {ExternalSymbolValue} from '../../docgen/docTypes';
 
 import {registerWidget} from '../Value';
 
 registerWidget<ExternalSymbolValue>('external', ({value}) => (
-  <ExternalHyperlink href={value.url}>{value.name}</ExternalHyperlink>
+  <>
+    <ExternalHyperlink href={value.url}>{value.name}</ExternalHyperlink>
+    {renderTypeParameters(value.typeParameters)}
+  </>
 ));