Correctly clip the TextBox

By adjusting only the x component of the size before turning it into a
rectangle, the right side of the rectangle gets moved, which allowed the
text to peak out on the right side. Inset already seems to do what
subtracting the border width there was possibly intended to do, so just
using the unadjusted size and then later insetting, resolves the problem
entirely.

Author: CryZe

druid/src/widget/textbox.rs

@@ -576,7 +576,7 @@ impl<T: TextStorage + EditableText> Widget<T> for TextBox<T> {
         };
 
         // Paint the background
-        let clip_rect = Size::new(size.width - border_width, size.height)
+        let clip_rect = size
             .to_rect()
             .inset(-border_width / 2.0)
             .to_rounded_rect(env.get(theme::TEXTBOX_BORDER_RADIUS));