docs: def _find_top_heading_level(self, content: str) -> int:
          '''Find the highest level heading (i.e. having the least '#'s)
          in a Markdown string.
  
          :param content: Markdown content
  
          :returns: Maximum heading level detected; if no heading is found, 0 is returned
          '''
  
          result = float('inf')
  
          for heading in self._heading_pattern.finditer(content):
              heading_level = len(heading.group('hashes'))
  
              if heading_level < result:
                  result = heading_level
  
              self.logger.debug(f'Maximum heading level: {result}')
  
          return result if result < float('inf') else 0