#1555570: correctly handle a \r\n that is split by the read buffer.

Patch and test by Tony Nelson.
diff --git a/Misc/NEWS b/Misc/NEWS
index 494fa1a..7abb564 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -473,6 +473,9 @@
 Library
 -------
 
+- Issue #1555570: email no longer inserts extra blank lines when a \r\n
+  combo crosses an 8192 byte boundary.
+
 - Issue #9243: Fix sndhdr module and add unit tests, contributed by James Lee.
 
 - ``ast.literal_eval()`` now allows byte literals.