Update db.h

include/rocksdb/db.h

@@ -175,7 +175,7 @@ class DB {
   // called before calling the desctructor so that the caller can get back a
   // status in case there are any errors. This will not fsync the WAL files.
   // If syncing is required, the caller must first call SyncWAL(), or Write()
-  // using am empty write batch with WriteOptions.sync=true.
+  // using an empty write batch with WriteOptions.sync=true.
   // Regardless of the return status, the DB must be freed. If the return
   // status is NotSupported(), then the DB implementation does cleanup in the
   // destructor