fix typo

(cherry picked from commit 967eb63b)

matlab/print_info.m

@@ -55,7 +55,7 @@ if ~noprint
         error('The steadystate file did not compute the steady state')
       case 20
         error(['Impossible to find the steady state. Either the model' ...
-               ' doesn''t have a steady state or there is an infinity of steady states' ...
+               ' doesn''t have a steady state, there are an infinity of steady states, ' ...
                ' or the guess values are too far from the solution'])
       case 21
         error('The steady state is complex')