A couple very minor typos

Change-Id: Ib82ea9d54179faec8ebbdb7be2b74c2bf0734e29
diff --git a/aos/flatbuffers.h b/aos/flatbuffers.h
index 392a7eb..da11edf 100644
--- a/aos/flatbuffers.h
+++ b/aos/flatbuffers.h
@@ -141,7 +141,7 @@
         std::string(reinterpret_cast<const char *>(other.data()), other.size());
   }
 
-  // Coppies the data from the other flatbuffer.
+  // Copies the data from the other flatbuffer.
   FlatbufferString &operator=(const Flatbuffer<T> &other) {
     data_ = std::string(other.data(), other.size());
     return *this;