docs: def renderer_doc(*args):
      '''
      Return the docstrings for all renderers. Optionally, specify a renderer or a
      function to narrow the selection.
  
      The strings are aggregated into a single document on the master for easy
      reading.
  
      Multiple renderers can be specified.
  
      .. versionadded:: 2015.5.0
  
      CLI Example:
  
      .. code-block:: bash
  
          salt '*' sys.renderer_doc
          salt '*' sys.renderer_doc cheetah
          salt '*' sys.renderer_doc jinja json
  
      Renderer names can be specified as globs.
  
      .. code-block:: bash
  
          salt '*' sys.renderer_doc 'c*' 'j*'
  
      '''
      renderers_ = salt.loader.render(__opts__, [])
      docs = {}
      if not args:
          for func in six.iterkeys(renderers_):
              docs[func] = renderers_[func].__doc__
          return _strip_rst(docs)
  
      for module in args:
          if '*' in module or '.' in module:
              for func in fnmatch.filter(renderers_, module):
                  docs[func] = renderers_[func].__doc__
          else:
              moduledot = module + '.'
              for func in six.iterkeys(renderers_):
                  if func.startswith(moduledot):
                      docs[func] = renderers_[func].__doc__
      return _strip_rst(docs)