Update ARC docs as objc_storeStrong returns void not id

llvm-svn: 348429
diff --git a/clang/docs/AutomaticReferenceCounting.rst b/clang/docs/AutomaticReferenceCounting.rst
index bf4d094..d6d5862 100644
--- a/clang/docs/AutomaticReferenceCounting.rst
+++ b/clang/docs/AutomaticReferenceCounting.rst
@@ -2284,7 +2284,7 @@
 
 .. _arc.runtime.objc_storeStrong:
 
-``id objc_storeStrong(id *object, id value);``
+``void objc_storeStrong(id *object, id value);``
 ----------------------------------------------
 
 *Precondition:* ``object`` is a valid pointer to a ``__strong`` object which is