patch 8.2.3777: spell file write error not checked

Problem:    Spell file write error not checked.
Solution:   Check writing the prefix conditions. (Bjorn Linse, closes #9323)

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3777,
 /**/
     3776,
 /**/