reduce table-of-contents depth to LaTeX subsections

doc/doxygen/refman.tex

@@ -1,6 +1,6 @@
 % StarPU --- Runtime system for heterogeneous multicore architectures.
 %
-% Copyright (C) 2013,2015-2016                           Inria
+% Copyright (C) 2013,2015-2016,2018                      Inria
 % Copyright (C) 2013-2017                                CNRS
 % Copyright (C) 2014,2018                                Université de Bordeaux
 %
@@ -54,6 +54,7 @@ Documentation License”.
 \end{figure}
 
 \pagenumbering{roman}
+\setcounter{tocdepth}{2}
 \tableofcontents
 \pagenumbering{arabic}
 \hypersetup{pageanchor=true,citecolor=blue}