finish implementing selection

src/main.odin

@@ -88,12 +88,13 @@ main :: proc() {
 			char := chars[0]
 			// TODO: selection
 			if selection.active {
+				delete_selection()
+				selection.active = false
+			}
 
-			} else {
 			inject_at(&lines[cursor.line], cursor.char, char)
 			cursor.char += 1
 		}
-		}
 
 		move_cursor()
 		handle_backspace()