Rename misnamed functions in geom/flat/orient

- Rename linearRingIsOriented => linearRingsAreOriented
  The function checks all linear rings of a Polygon, so
  the plural "rings" is more appropriate
- Rename linearRingsAreOriented => linearRingssAreOriented
  The double s is appropriate because the check is done for
  all Polygons of a MultiPolygon

This commit restores the function names from OpenLayers v4,
they were changed (wrongly IMHO) in #7820.

src/ol/geom/flat/orient.js

@@ -41,7 +41,7 @@ export function linearRingIsClockwise(flatCoordinates, offset, end, stride) {
  *     (counter-clockwise exterior ring and clockwise interior rings).
  * @return {boolean} Rings are correctly oriented.
  */
-export function linearRingIsOriented(flatCoordinates, offset, ends, stride, opt_right) {
+export function linearRingsAreOriented(flatCoordinates, offset, ends, stride, opt_right) {
   const right = opt_right !== undefined ? opt_right : false;
   for (let i = 0, ii = ends.length; i < ii; ++i) {
     const end = ends[i];
@@ -75,9 +75,9 @@ export function linearRingIsOriented(flatCoordinates, offset, ends, stride, opt_
  *     (counter-clockwise exterior ring and clockwise interior rings).
  * @return {boolean} Rings are correctly oriented.
  */
-export function linearRingsAreOriented(flatCoordinates, offset, endss, stride, opt_right) {
+export function linearRingssAreOriented(flatCoordinates, offset, endss, stride, opt_right) {
   for (let i = 0, ii = endss.length; i < ii; ++i) {
-    if (!linearRingIsOriented(
+    if (!linearRingsAreOriented(
       flatCoordinates, offset, endss[i], stride, opt_right)) {
       return false;
     }