Spelling fixes

Author: tschaub

src/geotiffimage.js

@@ -619,7 +619,7 @@ class GeoTIFFImage {
    * interleaved typed array.
    * Colorspaces other than RGB will be transformed to RGB, color maps expanded.
    * When no other method is applicable, the first sample is used to produce a
-   * greayscale image.
+   * grayscale image.
    * When provided, only a subset of the raster is read for each sample.
    *
    * @param {Object} [options] optional parameters

src/source/remote.js

@@ -85,9 +85,9 @@ class RemoteSource extends BaseSource {
       if (slices.length > 1) {
         // we requested more than one slice, but got only the first
         // unfortunately, some HTTP Servers don't support multi-ranges
-        // and return onyl the first
+        // and return only the first
 
-        // get the rest of the slices and fetch them iteratetively
+        // get the rest of the slices and fetch them iteratively
         const others = await Promise.all(slices.slice(1).map((slice) => this.fetchSlice(slice, signal)));
         return first.concat(others);
       }