Clarify when RedrawRequested is useful (#1529)

Co-Authored-By: Osspial <osspial@gmail.com>

src/lib.rs

@@ -73,14 +73,18 @@
 //!             // Application update code.
 //!
 //!             // Queue a RedrawRequested event.
+//!             //
+//!             // You only need to call this if you've determined that you need to redraw, in
+//!             // applications which do not always need to. Applications that redraw continuously
+//!             // can just render here instead.
 //!             window.request_redraw();
 //!         },
 //!         Event::RedrawRequested(_) => {
 //!             // Redraw the application.
 //!             //
-//!             // It's preferrable to render in this event rather than in MainEventsCleared, since
-//!             // rendering in here allows the program to gracefully handle redraws requested
-//!             // by the OS.
+//!             // It's preferable for applications that do not render continuously to render in
+//!             // this event rather than in MainEventsCleared, since rendering in here allows
+//!             // the program to gracefully handle redraws requested by the OS.
 //!         },
 //!         _ => ()
 //!     }