message: Fixes SignatureHelp interface does not agree with specification
diff: @@ -2392,16 +2392,28 @@ export interface SignatureHelp {
  signatures: SignatureInformation[];
  /**
  - * The active signature. Set to `null` if no
  - * signatures exist.
  + * The active signature. If omitted or the value lies outside the
  + * range of `signatures` the value defaults to zero or is ignored if
  + * the `SignatureHelp` has no signatures.
  + *
  + * Whenever possible implementors should make an active decision about
  + * the active signature and shouldn't rely on a default value.
  + *
  + * In future version of the protocol this property might become
  + * mandatory to better express this.
  */
  - activeSignature: uinteger | null;
  + activeSignature?: uinteger;
  /**
  - * The active parameter of the active signature. Set to `null`
  - * if the active signature has no parameters.
  + * The active parameter of the active signature. If omitted or the value
  + * lies outside the range of `signatures[activeSignature].parameters`
  + * defaults to 0 if the active signature has parameters. If
  + * the active signature has no parameters it is ignored.
  + * In future version of the protocol this property might become
  + * mandatory to better express the active parameter if the
  + * active signature does have any.
  */
  - activeParameter: uinteger | null;
  + activeParameter?: uinteger;
  }
  /**
  