docs: def _filter(self, text):
          """Context delimiter filter."""
  
          if self.line_endings:
              text = self.norm_nl(text)
  
          new_text = []
          index = 0
          last = 0
          end = len(text)
          while index < end:
              m = self.escapes.match(text, pos=index) if self.escapes else None
              if m:
                  index = m.end(0)
                  continue
              handled = False
              for delimiter in self.delimiters:
                  m = delimiter[0].match(text, pos=index)
                  if m:
                      if self.context_visible_first is True:
                          new_text.append(text[last:m.start(0)])
                      else:
                          new_text.append(m.group(delimiter[1]))
                      index = m.end(0)
                      last = index
                      handled = True
                      break
              if handled:
                  continue
              index += 1
          if last < end and self.context_visible_first is True:
              new_text.append(text[last:end])
  
          return ' '.join(new_text)