bpo-36582: Make collections.UserString.encode() return bytes, not str (GH-13138) (GH-15557)

(cherry picked from commit 2a16eea71f56c2d8f38c295c8ce71a9a9a140aff)

Co-authored-by: Daniel Fortunov <asqui@users.noreply.github.com>
diff --git a/Misc/ACKS b/Misc/ACKS
index ab874e9..5a8494f 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -509,6 +509,7 @@
 Michael Foord
 Amaury Forgeot d'Arc
 Doug Fort
+Daniel Fortunov
 Evens Fortuné
 Chris Foster
 John Fouhy
diff --git a/Misc/NEWS.d/next/Library/2019-05-07-17-42-36.bpo-36582.L_dxR6.rst b/Misc/NEWS.d/next/Library/2019-05-07-17-42-36.bpo-36582.L_dxR6.rst
new file mode 100644
index 0000000..34f16fc
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-05-07-17-42-36.bpo-36582.L_dxR6.rst
@@ -0,0 +1 @@
+Fix ``UserString.encode()`` to correctly return ``bytes`` rather than a ``UserString`` instance.
\ No newline at end of file