ui/app: update comment and fix typo

Signed-off-by: Elias Naur <mail@eliasnaur.com>

ui/app/app.go

@@ -18,7 +18,7 @@ type Draw struct {
 	Config *ui.Config
 	Size   image.Point
 	// Whether this draw is system generated
-	// and needs to a complete frame before
+	// and needs a complete frame before
 	// proceeding.
 	sync bool
 }

ui/ui.go

@@ -11,8 +11,8 @@ import (
 	"gioui.org/ui/internal/ops"
 )
 
-// Config contain the context for updating and
-// drawing a user interface.
+// Config contains the essential configuration for
+// updating and drawing a user interface.
 type Config struct {
 	// Device pixels per dp.
 	PxPerDp float32