Implement `OptionalVersionedTextDocumentIdentifier` for document versions

[genericptr]

For Sublime Text we currently do a hack which sets the document version to nil while using 0 for other editors. To remove the hack I think we need to use OptionalVersionedTextDocumentIdentifier since we currently aren't using document versions (which we probably should be doing unless it crashes Sublime Text)

See

For example:

    if ClientInfo.name = TClients.SublimeTextLSP then
      TextDocumentEdit.textDocument.version := nil
    else
      TextDocumentEdit.textDocument.version := 0;