patch 9.1.1115: [security]: use-after-free in str_to_reg()

Problem:  [security]: use-after-free in str_to_reg()
          (fizz-is-on-the-way)
Solution: when redirecting the :display command, check that one
          does not output to the register being displayed

Github Advisory:
https://github.com/vim/vim/security/advisories/GHSA-63p5-mwg2-787v

Signed-off-by: Christian Brabandt <cb@256bit.org>

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1115,
 /**/
     1114,
 /**/