docs(gen_help_html.lua): handle modeline and note nodes

[wookayin]

#28755 (comment)

Problem:

'modeline' and 'note' are unhandled in the online HTML documentation.

Some (not all) modelines are parsed by the vimdoc parser as a node of
type 'modeline'.

Solution:

• Ignore 'modeline' in HTML rendering.
• Render 'note' text in boldface.

Remark:

• Words like 'Deprecated' and 'Note' are parsed as 'note' rather than 'word'.
• I checked that there are no other unhandled nodes in the generated HTML files.

[clason]

If some modelines aren't parsed, please open an issue (or PR ;)) at neovim/tree-sitter-vimdoc.

[justinmk]

Some (not all) modelines are parsed by the vimdoc parser as a node

does that mean we still need this hack:

neovim/scripts/gen_help_html.lua

Lines 195 to 198 in cdd8722

	-- modeline
	-- Example: "vim:tw=78:ts=8:sw=4:sts=4:et:ft=help:norl:"
	or line:find('^%s*vim?%:.*ft=help')
	or line:find('^%s*vim?%:.*filetype=help')

[clason]

Let's try without and see how it goes. Parsing modelines is now the vimdoc parser's responsibility; papering over any shortcomings would be counterproductive.

[wookayin]

Yes, I agree that having a "proper" fix rather than a bandaid solution would be better: fixing the vimdoc parser to correctly handle all the modeline instances. I will take a look at the vimdoc parser.

[clason]

@wookayin I meant this in the sense of "this PR is fine and can be merged as-is" -- it's still an improvement, and any improvement in the vimdoc parser will be picked up automatically.

[clason]

The legacy modeline hack can be removed in a follow-up PR.