Show full exception error message when hovering over inline exception name

dependency on https://github.com/Almenon/AREPL-vscode/issues/324

I tested it with below and it worked!
```typescript
return {
range,
hoverMessage: `Traceback (most recent call last):
line 2, in
ValueError: foo`,
renderOptions: {
after: {
contentText: text
}
}
}
```