correct doc about list handler (ltluatex)

[Udi-Fogiel]

The documentation states that of all the functions in the callback returns true then the callback returns true as well, but the following example (and the code) shows that the return value in this case is the head passed to the callback.

\directlua{
luatexbase.create_callback('foo', 'list', false)
luatexbase.add_to_callback('foo', function(head) print('bar') return true end, 'baz') 
print(luatexbase.call_callback('foo', token.scan_list()))
}\hbox{foo}

\stop

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[davidcarlisle]

Yes this seems OK. The documentation was true when written but the code changed in 2021

2021-11-17  Marcel Krüger  <[email protected]>

	* ltluatex.dtx:
	Classify [hv]pack_quality callbacks as exclusive
	Never pass true to the engine for LuaTeX list callbacks