patch 8.2.4645: 'shortmess' changed when session does not store options

Problem:    'shortmess' changed when session does not store options.
Solution:   Save and restore 'shortmess' if needed. (James Charti,
            closes #10037)
diff --git a/src/version.c b/src/version.c
index 90b30ab..03778bd 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4645,
+/**/
     4644,
 /**/
     4643,