message: Allow null for version numbers
diff: @@ -1042,7 +1042,7 @@ export namespace VersionedTextDocumentIdentifier {
  * @param uri The document's uri.
  * @param uri The document's text.
  */
  - export function create(uri: string, version: number): VersionedTextDocumentIdentifier {
  + export function create(uri: string, version: number | null): VersionedTextDocumentIdentifier {
  return { uri, version };
  }
  @@ -1051,7 +1051,7 @@ export namespace VersionedTextDocumentIdentifier {
  */
  export function is(value: any): value is VersionedTextDocumentIdentifier {
  let candidate = value as VersionedTextDocumentIdentifier;
  - return Is.defined(candidate) && Is.string(candidate.uri) && Is.number(candidate.version);
  + return Is.defined(candidate) && Is.string(candidate.uri) && (candidate.version === null || Is.number(candidate.version));
  }
  }
  