docs: add InjectedStore to reference (#1976)

docs/docs/reference/prebuilt.md

@@ -10,6 +10,7 @@
       members:
         - ToolNode
         - InjectedState
+        - InjectedStore
         - tools_condition
 
 ::: langgraph.prebuilt.tool_validator

libs/langgraph/langgraph/prebuilt/tool_node.py

@@ -461,6 +461,9 @@ class InjectedStore(InjectedToolArg):
     the store will be automatically propagated to the tools with InjectedStore args
     when using ToolNode.
 
+    !!! Warning
+        `InjectedStore` annotation requires `langchain-core >= 0.3.8`
+
     Example:
         ```python
         from typing import Any