Typo fix.

include/niflib.h

@@ -144,13 +144,13 @@ NIFLIB_API Ref<NiObject> ReadNifTree( istream & in, NifInfo * info = NULL );
 
 /*!
  * Creates a new NIF file of the given file name by crawling through the data tree starting with the root objects given, and keeps track of links that cannot been written.
- * \param[in] in The output stream to write the NIF data to.
+ * \param[in] out The output stream to write the NIF data to.
  * \param[in] roots The root objects to start from when writing out the NIF file.  All decedents of these blocks will be written to the file in tree-descending order.
  * \param[in] missing_link_stack stack of links which are referred to but which are not inside the tree rooted by roots.
  * \param[in] info A NifInfo structure that contains information such as the version of the NIF file to create.
  * \sa ReadNifList, WriteNifTree
  */
-NIFLIB_API void WriteNifTree( ostream & in, list<NiObjectRef> const & roots, list<NiObject *> & missing_link_stack, const NifInfo & info = NifInfo() );
+NIFLIB_API void WriteNifTree( ostream & out, list<NiObjectRef> const & roots, list<NiObject *> & missing_link_stack, const NifInfo & info = NifInfo() );
 
 /*!
  * Creates a new NIF file of the given file name by crawling through the data tree starting with the root object given.