patch 8.2.1770: invalid memory use when using SpellFileMissing autocmd

Problem:    Invalid memory use when using SpellFileMissing autocmd.
Solution:   Add test case. (Dominique Pellé, closes #7036)  Fix using a window
            that was closed.
diff --git a/src/version.c b/src/version.c
index 3d37c85..26e63c2 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1770,
+/**/
     1769,
 /**/
     1768,