update docs

documentation/en/api-methods.md

@@ -3243,7 +3243,7 @@ Response:
 
 ## State
 The State methods are used to query, inspect, and interact with chain state.
-Most methods take a TipSetKey as a parameter. The state looked up is the state at that tipset.
+Most methods take a TipSetKey as a parameter. The state looked up is the parent state of the tipset.
 A nil TipSetKey can be provided as a param, this will cause the heaviest tipset in the chain to be used.
 
 
@@ -3296,6 +3296,10 @@ Response: `null`
 ### StateCall
 StateCall runs the given message and returns its result without any persisted changes.
 
+StateCall applies the message to the tipset's parent state. The
+message is not applied on-top-of the messages in the passed-in
+tipset.
+
 
 Perms: read