add scaladoc, update changelog

Signed-off-by: James Santucci <[email protected]>

Author: jisantuc

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Remove explicit unused Scaffeine dependency from projects [#3314](https://github.com/locationtech/geotrellis/pull/3314)
 - Remove an excessive close after the abort call in S3RangeReader [#3324](https://github.com/locationtech/geotrellis/pull/3324)
 - Fix sigmoidal contrast calculation [#3328](https://github.com/locationtech/geotrellis/pull/3328)
+- Separated monoidal component of `vectortile.StrictLayer` [#3330](https://github.com/locationtech/geotrellis/pull/3330)
 
 ## [3.5.1] - 2020-11-23
 

vectortile/src/main/scala/geotrellis/vectortile/MVTFeatures.scala

@@ -26,6 +26,13 @@ import geotrellis.vector.{
 }
 import cats.Monoid
 
+/** Container case class for collections of [[MVTFeature]]s
+  *
+  * This is separated for ease of use when reading geometries from
+  * places. With the `Monoid` instance for `MVTFeatures`, each geometry
+  * can be lifted into a seq in the relevant attribute, and then
+  * the separate `MVTFeatures` case classes can all be combined.
+  */
 final case class MVTFeatures(
   /** Every Point Feature in this Layer. */
   points: Seq[MVTFeature[Point]],