how to get rid of descriptions that are linked to input types?
The Better Formats module is your friend here, you can use it to remove all or part of the format descriptions/options:


  Better formats is a module to add more flexibility to Drupal's core input format system.
  
  ...
  
  
  Set the default format per role.
  Set the default format per content type.
  Control allowed formats per content type.
  Hide format tips.
  Hide more format tips link.
  Hide format selection for nodes, comments, and blocks seperately, forcing the default to be used.
  
  
  ...


(emphasis mine)