[AST] Add missing deque include

Presumably previously found in some other include. Include it directly.

Author: bnbarham

lib/AST/NameLookup.cpp

@@ -49,6 +49,8 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 
+#include <deque>
+
 #define DEBUG_TYPE "namelookup"
 
 using namespace swift;