patch 8.1.0583: using illogical name for get_dict_number()/get_dict_string()

Problem:    Using illogical name for get_dict_number()/get_dict_string().
Solution:   Rename to start with dict_.
diff --git a/src/eval.c b/src/eval.c
index 8839e05..18aa5e5 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -4063,7 +4063,7 @@
      */
     case '{':	ret = get_lambda_tv(arg, rettv, evaluate);
 		if (ret == NOTDONE)
-		    ret = get_dict_tv(arg, rettv, evaluate);
+		    ret = dict_get_tv(arg, rettv, evaluate);
 		break;
 
     /*