Improve scrollbar behavior (#351)

* Change scrollbar behavior

* Leave space at the end of the scrollbar

* Change mid to center

* Use shorter array initialization

* Add space around scrollbar

* Fix scrollbar spacing

* Smooth end of scrollbars

* Add page up and down

* Page up and down on click in scrollbar track

* Add shift pageup to translate horizontally

frontend/wasm/src/wrappers.rs

@@ -151,6 +151,8 @@ pub fn translate_key(name: &str) -> Key {
 		"]" => KeyRightBracket,
 		"{" => KeyLeftCurlyBracket,
 		"}" => KeyRightCurlyBracket,
+		"pageup" => KeyPageUp,
+		"pagedown" => KeyPageDown,
 		_ => UnknownKey,
 	}
 }