drawTimer: fix type of parameter

The elapsed is passed to something
that expects a number, so use that
type for the parameter itself.

lib/ReactViews/Generic/Timer/drawTimer.js

@@ -155,7 +155,7 @@ export function createTimer(
  * @param {string} containerId The id of the element to insert the timer into.
  * @param {string} elapsedTimeClass A class for styling the animation that fills the timer as it runs.
  * @param {string} backgroundClass A class for styling the timer's background circle.
- * @param {string} [elapsed=0] How much time (in seconds) has already passed.
+ * @param {number} [elapsed=0] How much time (in seconds) has already passed.
  */
 export function startTimer(
   radius,