Add missing gpu argument in API doc for matfaust.fact.hierarchical.

wrapper/matlab/+matfaust/+fact/hierarchical.m

@@ -8,6 +8,8 @@
 %> - {'rectmat', j, k, s} to use pre-defined parameters used for instance in factorization of the MEG matrix which is a rectangular matrix of size m*n such that m < n (see matfaust.demo.bsl); j is the number of factors, k the sparsity of the main factor's columns, and s the sparsity of rows for all other factors except the residuum (that is the first factor here because the factorization is made toward the left -- is_side_fact_left == true, cf. matfaust.factparams.ParamsHierarchical).
 %> </br>The residuum has a sparsity of P*rho^(num_facts-1). <br/> By default, rho == .8 and P = 1.4. It's possible to set custom values with for example p == { 'rectmat', j, k, s, 'rho', .4, 'P', .7}. <br/>The sparsity is here the number of non-zero elements.
 %> @param 'backend',int (optional) the backend (the C++ implementation) chosen. Must be 2016 (the default) or 2020 (which should be quicker for certain configurations - e.g. factorizing a Hadamard matrix).
+%> @param 'gpu', bool (optional) set to true to execute the algorithm using the GPU implementation. This option is only available when backend==2020.
+%>
 %> @note - The fully defined parameters (ParamsHierarchical instance) used/generated by the function are available in the return result (so one can consult what precisely mean the simplified parameterizations and possibly adjust the attributes to factorize again).
 %> @note - This function has its shorthand matfaust.faust_fact(). For convenience you might use it like this:
 %> @code

wrapper/matlab/+matfaust/+fact/palm4msa.m

@@ -5,7 +5,7 @@
 %> @param M the dense matrix to factorize.
 %> @param p the matfaust.factparams.ParamsPalm4MSA instance to define the algorithm parameters.
 %> @param 'backend',int (optional) the backend (the C++ implementation) chosen. Must be 2016 (the default) or 2020 (which should be quicker for certain configurations - e.g. factorizing a Hadamard matrix).
-%> @param 'gpu', bool (optional) set to true to execute the algorithm using the GPU implementation. This options is only available when backend==2020.
+%> @param 'gpu', bool (optional) set to true to execute the algorithm using the GPU implementation. This option is only available when backend==2020.
 %>
 %> @retval F the Faust object result of the factorization.
 %> @retval [F, lambda] = palm4msa(M, p) to optionally get lambda (scale).