datatomfile: Consistently replace char by cell arrays

Required after https://github.com/DynareTeam/dynare/commit/7be8f10e0e035e503c391979ae41415ffaf64e0a

tests/estimation/fs2000_stochastic_singularity_xfail.mod

@@ -64,7 +64,7 @@ var e_junk; stderr 0.005;
 end;
 
 stoch_simul(order=1,periods=300,irf=0,nomoments) k y c;
-datatomfile('fsdat_simul_collinear', char('k','y','c'));
+datatomfile('fsdat_simul_collinear', {'k'; 'y'; 'c'});
 
 estimated_params;
 alp, beta_pdf, 0.356, 0.02;

tests/filter_step_ahead/fs2000_filter_step_ahead_ML.mod

@@ -118,4 +118,4 @@ estimation(order=1, datafile='../fs2000/fsdat_simul', nobs=192, loglinear, filte
  */
 
 //stoch_simul(periods=200, order=1);
-//datatomfile('fsdat_simul', char('gy_obs', 'gp_obs'));
+//datatomfile('fsdat_simul', {gy_obs'; 'gp_obs'});

tests/filter_step_ahead/fs2000_filter_step_ahead_bayesian.mod

@@ -124,4 +124,4 @@ estimation(order=1, datafile='../fs2000/fsdat_simul', nobs=192, loglinear, mh_re
  */
 
 //stoch_simul(periods=200, order=1);
-//datatomfile('fsdat_simul', char('gy_obs', 'gp_obs'));
+//datatomfile('fsdat_simul', {'gy_obs'; 'gp_obs'});

tests/fs2000/fs2000_missing_data.mod

@@ -90,4 +90,4 @@ estimation(order=1, datafile=fsdat_simul_missing_obs, nobs=192, loglinear, mh_re
  */
 
 //stoch_simul(periods=200, order=1);
-//datatomfile('fsdat_simul', char('gy_obs', 'gp_obs'));
+//datatomfile('fsdat_simul', {'gy_obs'; 'gp_obs'});

tests/fs2000/fs2000a.mod

@@ -92,4 +92,4 @@ estimation(order=1,datafile=fsdat_simul,nobs=192,loglinear,mh_replic=2000,
            mode_compute=4,mh_nblocks=2,mh_drop=0.45,mh_jscale=0.65,diffuse_filter);
 
 //stoch_simul(order=1, periods=200);
-//datatomfile('fsdat_simul2', char('gy_obs', 'gp_obs', 'Y_obs', 'P_obs'));
+//datatomfile('fsdat_simul2', {'gy_obs'; 'gp_obs'; 'Y_obs'; 'P_obs'});

tests/kalman_filter_smoother/fs2000_smoother_only.mod

@@ -113,4 +113,4 @@ estimation(order=1, datafile=fsdat_simul, mode_compute=0,nobs=192, loglinear, sm
  */
 
 //stoch_simul(periods=200, order=1);
-//datatomfile('fsdat_simul', char('gy_obs', 'gp_obs'));
+//datatomfile('fsdat_simul', {'gy_obs'; 'gp_obs'});

tests/kalman_filter_smoother/fs2000_smoother_only_ns.mod

@@ -118,4 +118,4 @@ estimation(order=1, datafile=fsdat_simul, mode_compute=0,nobs=192, loglinear,dif
  */
 
 //stoch_simul(periods=200, order=1);
-//datatomfile('fsdat_simul', char('gy_obs', 'gp_obs'));
+//datatomfile('fsdat_simul', {'gy_obs'; 'gp_obs'});