patch 8.0.0160: EMSG() is sometimes used where it should be IEMSG()

Problem:    EMSG() is sometimes used for internal errors.
Solution:   Change them to IEMSG(). (Dominique Pelle)  And a few more.
diff --git a/src/version.c b/src/version.c
index f1a36da..641c72c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    160,
+/**/
     159,
 /**/
     158,