Method updateCursorStyle

src/browser/CoreBrowserTerminal.ts:859–865

* Change the cursor style for different selection modes

(ev: KeyboardEvent | MouseEvent)

   * Change the cursor style for different selection modes
   */
  public updateCursorStyle(ev: KeyboardEvent | MouseEvent): void {
    if (this._selectionService?.shouldColumnSelect(ev)) {
      this.element!.classList.add('column-select');
    } else {
      this.element!.classList.remove('column-select');
    }
  }

  /**
   * Display the cursor element