bug#65554: 30.0.50; help-echo string for truncated tab-bar names is not viewable

[Juri Linkov]

>> Next I could rename tab-bar-tab-name-format-function to
>> tab-bar-tab-name-format-functions with the default value
>> composed from the code fragments of tab-bar-tab-name-format-default:
>>
>>   '(tab-bar-tab-name-format-hints
>>     tab-bar-tab-name-format-close-button
>>     tab-bar-tab-name-format-face
>>    )
>>
>> Then you will be able to customize it to:
>>
>>   '(tab-bar-tab-name-format-truncate
>>     tab-bar-tab-name-format-hints
>>     tab-bar-tab-name-format-close-button
>>     tab-bar-tab-name-format-face
>>    )
>>
>> That first will truncate the tab name, then add numeric hints to the
>> truncated name, then add the close button, then put faces on the final string
>> that will be displayed on the tab bar.
>
> That would be much more convenient, and make the customisation around
> the tab name a lot less confusing.

Now tab-bar-tab-name-format-functions is pushed to master.

Please try to customize it and add tab-bar-tab-name-format-truncated
to the top of the list.

PS: I think no functions/defcustoms should be obsoleted with this change.