patch 8.2.4683: verbose check with dict_find() to see if a key is present

Problem:    Verbose check with dict_find() to see if a key is present.
Solution:   Add dict_has_key(). (Yegappan Lakshmanan, closes #10074)
diff --git a/src/filepath.c b/src/filepath.c
index 3786ef6..1bde420 100644
--- a/src/filepath.c
+++ b/src/filepath.c
@@ -1605,7 +1605,7 @@
 	return FAIL;
     }
 
-    if (dict_find(tv->vval.v_dict, (char_u *)"sort", -1) != NULL)
+    if (dict_has_key(tv->vval.v_dict, "sort"))
 	compare = dict_get_string(tv->vval.v_dict, (char_u *)"sort", FALSE);
     else
     {