parameters: (self, separator: str = " ")
docstring: Join the next line to the current one by deleting the line ending after
          the current line.
docstring_summary: Join the next line to the current one by deleting the line ending after
          the current line.
docstring_tokens: Join the next line to the current one by deleting the line ending after the current line .
function: def join_next_line(self, separator: str = " ") -> None:
          """
          Join the next line to the current one by deleting the line ending after
          the current line.
          """
          if not self.document.on_last_line:
              self.cursor_position += self.document.get_end_of_line_position()
              self.delete()
  
              # Remove spaces.
              self.text = (
                  self.document.text_before_cursor
                  + separator
                  + self.document.text_after_cursor.lstrip(" ")
              )
function_tokens: def join_next_line ( self , separator : str = " " ) -> None : if not self . document . on_last_line : self . cursor_position += self . document . get_end_of_line_position ( ) self . delete ( ) # Remove spaces. self . text = ( self . document . text_before_cursor + separator + self . document . text_after_cursor . lstrip ( " " ) )