message: fix(history-tracker): handle when editor is null
diff: @@ -192,7 +192,6 @@ export class HistoryTracker {
  constructor(vimState: VimState) {
  this.vimState = vimState;
  -
  this._initialize();
  }
  @@ -223,7 +222,7 @@ export class HistoryTracker {
  }
  private _getDocumentText(): string {
  - return (this.vimState.editor.document && this.vimState.editor.document.getText()) || '';
  + return (this.vimState.editor && this.vimState.editor.document && this.vimState.editor.document.getText()) || '';
  }
  private _addNewHistoryStep(): void {
  