minor improvements and scalafmt

Author: Angel-O

core/shared/src/main/scala/fs2/Stream.scala

@@ -1429,13 +1429,13 @@ final class Stream[+F[_], +O] private[fs2] (private[fs2] val underlying: Pull[F,
             (isBufferEmpty, supplyEnded.get).mapN(_ && _)
 
           //  releasing a number of permits equal to {groupSize} is enough in most cases, but in
-          //  order to ensure prompt termination of the consumer on interruption when the timeout
+          //  order to ensure prompt termination of the consumer on interruption even when the timeout
           //  has not kicked in yet nor we've seen enough elements we need to max out the supply
           val maxOutSupply =
             supply.available.flatMap(av => supply.releaseN(Long.MaxValue - av))
 
-          // enabling termination of the consumer stream when the producer completes
-          // naturally (i.e runs out of elements)
+          // enabling termination of the consumer stream when the producer completes naturally
+          // (i.e runs out of elements) or when the combined stream (consumer + producer) is interrupted
           val endSupply: F2[Unit] = supplyEnded.set(true) *> maxOutSupply
 
           val enqueue: F2[Unit] =

core/shared/src/test/scala/fs2/StreamCombinatorsSuite.scala

@@ -833,7 +833,7 @@ class StreamCombinatorsSuite extends Fs2Suite {
         .assertEquals(0.millis)
     }
 
-    test("Upstream failures are propagated downstream") {
+    test("upstream failures are propagated downstream") {
 
       case object SevenNotAllowed extends NoStackTrace
 
@@ -847,7 +847,7 @@ class StreamCombinatorsSuite extends Fs2Suite {
       downstream.compile.lastOrError.intercept[SevenNotAllowed.type]
     }
 
-    test("Upstream interruption causes immediate downstream termination with all elements being released") {
+    test("upstream interruption causes immediate downstream termination with all elements being emitted") {
 
       val sourceTimeout = 5.5.seconds
       val downstreamTimeout = sourceTimeout + 2.seconds
@@ -868,7 +868,7 @@ class StreamCombinatorsSuite extends Fs2Suite {
               // specified, unless source ends, due to interruption or
               // natural termination (i.e runs out of elements)
               val downstream: Stream[IO, Chunk[Int]] =
-                source.groupWithin(Int.MaxValue / 2 + 4, 1.day)
+                source.groupWithin(Int.MaxValue, 1.day)
 
               downstream.compile.lastOrError
                 .map(_.toList)