add backlink to tc39/ecma262#562

README.md

@@ -7,6 +7,10 @@
 * Main author: Claude Pache ([@claudepache](https://github.com/claudepache))
 * Champion: Mark S. Miller ([@erights](https://github.com/erights))
 
+## Previous discussion
+
+* [tc39/ecma262#562](https://github.com/tc39/ecma262/issues/562)
+
 ## Introduction
 
 Deprecated (as it breaks encapsulation provided by functions), but needed for web compatibility.
@@ -18,7 +22,6 @@ Goals:
 * Cross-realm leakages are prevented.
 * It is easy to completely remove the functionality for a given realm.
 
-
 In annex B.
 
 > NOTE. Implementations have historically provided “caller” and “arguments” magic properties on functions. The following semantics allow them to keep backward compatibility with those deprecated features while limiting the API surface and safely restricting their functionality to some class of legacy functions and avoiding any cross-realm leakages.