Add 0-character during in-situ numbers-as-strings parsing

include/rapidjson/reader.h

@@ -1290,9 +1290,10 @@ private:
 
             if (parseFlags & kParseInsituFlag) {
                 s.Pop();  // Pop stack no matter if it will be used or not.
-                typename InputStream::Ch *head = is.PutBegin();
+                typename InputStream::Ch* head = is.PutBegin();
                 const size_t length = s.Tell() - startOffset;
                 RAPIDJSON_ASSERT(length <= 0xFFFFFFFF);
+                *(head + length) = '\0';
                 const typename TargetEncoding::Ch* const str = reinterpret_cast<typename TargetEncoding::Ch*>(head);
                 cont = handler.RawNumber(str, SizeType(length), false);
             }