Fix function prototype.

Author: qiongsiwu

clang/tools/libclang/CXString.h

@@ -70,7 +70,7 @@ CXString createCXString(CXStringBuf *buf);
 /// Create a CXStringSet object owns the strings. Such an object should be
 /// disposed with clang_disposeStringSet.
 CXStringSet *createSet(const std::vector<std::string> &Strings);
-CXStringSet *createSet(const std::vector<StringRef> &Strings);
+CXStringSet *createRefSet(ArrayRef<StringRef> Strings);
 
 /// A string pool used for fast allocation/deallocation of strings.
 class CXStringPool {