Fix typos, remove unused functions

The functions are already defined in `src/util/mapbox.ts`

src/util/util.ts

@@ -337,7 +337,7 @@ export function isCounterClockwise(a: Point, b: Point, c: Point): boolean {
 }
 
 /**
- * Returns the signed area for the polygon ring.  Postive areas are exterior rings and
+ * Returns the signed area for the polygon ring.  Positive areas are exterior rings and
  * have a clockwise winding.  Negative areas are interior rings and have a counter clockwise
  * ordering.
  *
@@ -409,7 +409,7 @@ export function sphericalToCartesian([r, azimuthal, polar]: [number, number, num
 
 /* global self, WorkerGlobalScope */
 /**
- *  Retuns true if the when run in the web-worker context.
+ *  Returns true if the when run in the web-worker context.
  *
  * @private
  * @returns {boolean}
@@ -500,12 +500,3 @@ export function b64DecodeUnicode(str: string) {
         return '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2); //eslint-disable-line
     }).join(''));
 }
-
-const mapboxHTTPURLRe = /^((https?:)?\/\/)?([^\/]+\.)?mapbox\.c(n|om)(\/|\?|$)/i;
-export function isMapboxHTTPURL(url: string): boolean {
-    return mapboxHTTPURLRe.test(url);
-}
-
-export function hasCacheDefeatingSku(url: string) {
-    return url.indexOf('sku=') > 0 && isMapboxHTTPURL(url);
-}