patch 8.0.0720: unfinished mapping not displayed when running timer

Problem:    Unfinished mapping not displayed when running timer.
Solution:   Also use the extra_char while waiting for a mapping and digraph.
            (closes #1844)
diff --git a/src/version.c b/src/version.c
index bd274f7..0d5db7f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    720,
+/**/
     719,
 /**/
     718,