[docmaker] Allow references to section names.

In the reference, we show the section's title enclosed in single
quotes.

* src/tools/docmaker/formatter.py (Formatter::__init__): Collect
section names as identifiers.

* src/tools/docmaker/tohtml.py (section_title_header): Split into...
(section_title_header1, section_title_header2): ... these two
strings.
(HtmlFormatter::make_block_url, make_html_word, html_source_quote):
Handle sections.
(HtmlFormatter::section_enter): Updated to add `id' HTML attribute.
3 files changed