Improve some null types for strictNullChecks

src/ol/geom/LineString.js

@@ -166,7 +166,7 @@ class LineString extends SimpleGeometry {
    *
    * @param {number} m M.
    * @param {boolean} [opt_extrapolate] Extrapolate. Default is `false`.
-   * @return {import("../coordinate.js").Coordinate} Coordinate.
+   * @return {import("../coordinate.js").Coordinate|null} Coordinate.
    * @api
    */
   getCoordinateAtM(m, opt_extrapolate) {

src/ol/geom/MultiLineString.js

@@ -169,7 +169,7 @@ class MultiLineString extends SimpleGeometry {
    * @param {number} m M.
    * @param {boolean} [opt_extrapolate] Extrapolate. Default is `false`.
    * @param {boolean} [opt_interpolate] Interpolate. Default is `false`.
-   * @return {import("../coordinate.js").Coordinate} Coordinate.
+   * @return {import("../coordinate.js").Coordinate|null} Coordinate.
    * @api
    */
   getCoordinateAtM(m, opt_extrapolate, opt_interpolate) {

src/ol/geom/Polygon.js

@@ -275,7 +275,7 @@ class Polygon extends SimpleGeometry {
    * at index `1` and beyond.
    *
    * @param {number} index Index.
-   * @return {LinearRing} Linear ring.
+   * @return {LinearRing|null} Linear ring.
    * @api
    */
   getLinearRing(index) {

src/ol/geom/flat/interpolate.js

@@ -74,7 +74,7 @@ export function interpolatePoint(
  * @param {number} stride Stride.
  * @param {number} m M.
  * @param {boolean} extrapolate Extrapolate.
- * @return {import("../../coordinate.js").Coordinate} Coordinate.
+ * @return {import("../../coordinate.js").Coordinate|null} Coordinate.
  */
 export function lineStringCoordinateAtM(
   flatCoordinates,
@@ -147,7 +147,7 @@ export function lineStringCoordinateAtM(
  * @param {number} m M.
  * @param {boolean} extrapolate Extrapolate.
  * @param {boolean} interpolate Interpolate.
- * @return {import("../../coordinate.js").Coordinate} Coordinate.
+ * @return {import("../../coordinate.js").Coordinate|null} Coordinate.
  */
 export function lineStringsCoordinateAtM(
   flatCoordinates,

src/ol/geom/flat/textpath.js

@@ -17,7 +17,7 @@ import {rotate} from './transform.js';
  * @param {string} font The font.
  * @param {Object<string, number>} cache A cache of measured widths.
  * @param {number} rotation Rotation to apply to the flatCoordinates to determine whether text needs to be reversed.
- * @return {Array<Array<*>>} The result array (or null if `maxAngle` was
+ * @return {Array<Array<*>>|null} The result array (or null if `maxAngle` was
  * exceeded). Entries of the array are x, y, anchorX, angle, chunk.
  */
 export function drawTextOnPath(