* tta/C/convert/convert_to_plaintext.c
(plaintext_convert_output_unit),
tta/perl/Texinfo/Convert/PlaintextNonXS.pm (convert_output_unit):
remove _stream_reset, it is not useful, as stream_final_result
already do it.

* tta/perl/Texinfo/Convert/PlaintextNonXS.pm (_stream_to_text)
(_convert): reset pending_text in _stream_to_text.  Use
_pending_to_text for text_before_first_node, as we want to
keep the pending text for conversion.