starlark: add missing binary ops to doc comment
diff --git a/starlark/value.go b/starlark/value.go
index 1907ecb..6f56fbc 100644
--- a/starlark/value.go
+++ b/starlark/value.go
@@ -268,7 +268,8 @@
var _ HasSetKey = (*Dict)(nil)
// A HasBinary value may be used as either operand of these binary operators:
-// + - * / % in not in | &
+// + - * / // % in not in | & ^ << >>
+//
// The Side argument indicates whether the receiver is the left or right operand.
//
// An implementation may decline to handle an operation by returning (nil, nil).