patch 9.0.0765: with a Visual block a put command column may go negative

Problem:    With a Visual block a put command column may go negative.
Solution:   Check that the column does not become negative.
diff --git a/src/version.c b/src/version.c
index dc5e401..017b311 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    765,
+/**/
     764,
 /**/
     763,