stack: bump to lts-17; comment

Author: simonmichael

stack.yaml

@@ -1,9 +1,10 @@
-resolver: lts-16.25
+resolver: lts-17.15
 
 packages:
 - '.'
 
 extra-deps:
-# https://github.com/docopt/docopt.hs/issues/33
+# This is https://github.com/docopt/docopt.hs/pull/34 supporting MonadFail.
+# More context at https://github.com/docopt/docopt.hs/issues/33.
 - git: [email protected]:gelisam/docopt.hs
   commit: 16dc7bc596c0ea4fa4466b12f474b1abfa72c885