LibVT: Set scrollbar page size

Author: https://github.com/tomuta
Commit: https://github.com/SerenityOS/serenity/commit/df542299546
Pull-request: https://github.com/SerenityOS/serenity/pull/2749

Libraries/LibVT/TerminalWidget.cpp

@@ -432,6 +432,7 @@ void TerminalWidget::relayout(const Gfx::IntSize& size)
         size.height() - frame_thickness() * 2,
     };
     m_scrollbar->set_relative_rect(scrollbar_rect);
+    m_scrollbar->set_page(new_rows);
 }
 
 Gfx::IntSize TerminalWidget::compute_base_size() const