Fixed one last reference to HeteroC

hpvm/docs/how_to_guides/writing-heteroc-program.rst

@@ -65,7 +65,7 @@ manually outline a particular region of code into its own function to
 utilize the previous ``__hetero__launch`` call. For such cases, we
 introduced an additional launching marker, ``__hetero__launch_begin``
 which enables user’s to simply define the region of code which they want
-to be extracted and the ``HeteroC++`` api will automatically outline the
+to be extracted and the ``Hetero-C++`` api will automatically outline the
 code accordingly and insert the ``__hetero__launch`` call with the
 appropriate arguments.