Fixed doxygen blocks
(cherry picked from commit 77db6ce3481ad610ee786d5ab171d5d10c1cb59d)
diff --git a/include/polarssl/bignum.h b/include/polarssl/bignum.h
index aed779d..474324a 100644
--- a/include/polarssl/bignum.h
+++ b/include/polarssl/bignum.h
@@ -184,7 +184,7 @@
  */
 int mpi_lset( mpi *X, t_sint z );
 
-/*
+/**
  * \brief          Get a specific bit from X
  *
  * \param X        MPI to use
@@ -194,7 +194,7 @@
  */
 int mpi_get_bit( mpi *X, size_t pos );
 
-/*
+/**
  * \brief          Set a bit of X to a specific value of 0 or 1
  *
  * \note           Will grow X if necessary to set a bit to 1 in a not yet