patch 8.2.3436: check for optional bool type has confusing return type

Problem:    Check for optional bool type has confusing return type.
Solution:   Explicitly return OK.

src/typval.c

@@ -459,13 +459,15 @@ check_for_bool_arg(typval_T *args, int idx)
 }
 
 /*
- * Check for an optional bool argument at 'idx'
+ * Check for an optional bool argument at 'idx'.
+ * Return FAIL if the type is wrong.
  */
     int
 check_for_opt_bool_arg(typval_T *args, int idx)
 {
-    return (args[idx].v_type == VAR_UNKNOWN
-	    || check_for_bool_arg(args, idx) != FAIL);
+    if (args[idx].v_type == VAR_UNKNOWN)
+	return OK;
+    return check_for_bool_arg(args, idx);
 }
 
 /*

src/version.c

@@ -755,6 +755,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3436,
 /**/
     3435,
 /**/