fix documentation INPUT_GET_VOUTS actually uses size_t* than int*

(cherry picked from commit e575df71f59dcc2d9ce7c694ed5fb2b1d307e0ec)
Signed-off-by: Rémi Duraffort <ivoire@videolan.org>

include/vlc_input.h

@@ -512,7 +512,7 @@ enum input_query_e
     /* Input ressources
      * XXX You must call vlc_object_release as soon as possible */
     INPUT_GET_AOUT,         /* arg1=aout_instance_t **              res=can fail */
-    INPUT_GET_VOUTS,        /* arg1=vout_thread_t ***, int *        res=can fail */
+    INPUT_GET_VOUTS,        /* arg1=vout_thread_t ***, size_t *        res=can fail */
     INPUT_GET_ES_OBJECTS,   /* arg1=int id, vlc_object_t **dec, vout_thread_t **, aout_instance_t ** */
 
     /* External clock managments */