bug#60511: 29.0.50; treesit-ready-p should not emit warning by default

[Juri Linkov <juri@linkov.net>]

>> >> I can make treesit-ready-p not emit any warning by default, and change
>> >> the quiet parameter to WARN, and accept either 'warn or ‘message.
>> >>
>> >> Basically:
>> >>
>> >> (treesit-ready-p lang) => t/nil
>> >> (treesit-ready-p lang 'warn) => t/emit warning
>> >> (treesit-ready-p lang 'message) => t/message
>> >>
>> >> Eli, WDYT?
>> >
>> > I think the default should be to emit a warning, like we do now.
>>
>> Then how users could change this default?
>
> In what situation?
>
> If they invoke the mode, they aren't supposed to disable the warning,
> and they cannot.

In a situation when they want simply to visit a file without using
tree-sitter features, and that visit won't require from them
customization with modifying auto-mode-alist, etc.