Recommend soong_config_set instead of add_soong_config_var_value

Bug: None
Test: Presubmits
Change-Id: Ib6726436f8eea1b46ce4c30febeae6180f21cceb
diff --git a/README.md b/README.md
index b820fd1..127c52c 100644
--- a/README.md
+++ b/README.md
@@ -452,10 +452,9 @@
 
 The values of the variables can be set from a product's `BoardConfig.mk` file:
 ```
-$(call add_soong_config_namespace, acme)
-$(call add_soong_config_var_value, acme, board, soc_a)
-$(call add_soong_config_var_value, acme, feature, true)
-$(call add_soong_config_var_value, acme, width, 200)
+$(call soong_config_set,acme,board,soc_a)
+$(call soong_config_set,acme,feature,true)
+$(call soong_config_set,acme,width,200)
 ```
 
 The `acme_cc_defaults` module type can be used anywhere after the definition in