patch 8.2.0827: Vim9: crash in :defcompile

Problem:    Vim9: crash in :defcompile.
Solution:   Fix off-by-one error.

src/userfunc.c

@@ -3348,6 +3348,7 @@ ex_defcompile(exarg_T *eap UNUSED)
 		    hi = func_hashtab.ht_array;
 		    ht_used = func_hashtab.ht_used;
 		    todo = (int)ht_used;
+		    --hi;
 		}
 	    }
 	}

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    827,
 /**/
     826,
 /**/