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

[Juri Linkov]

>> 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?