patch 8.1.0819: a failed assert with a long string is hard to read

Problem:    A failed assert with a long string is hard to read.
Solution:   Shorten the assert message.
diff --git a/src/version.c b/src/version.c
index 4beae27..3a75c99 100644
--- a/src/version.c
+++ b/src/version.c
@@ -788,6 +788,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    819,
+/**/
     818,
 /**/
     817,