Setting Tabs::tab_bar_width to Length::Shrink doesn't respect the content of the individual tabs

[mfreeborn]

The quickest way to demonstrate is to add .tab_bar_width(Length::Shrink) immediately after Line 133 in the example.

The result is this:

I would expect (indeed, what I am trying to achieve) that the tabs shrink down to the smallest width that would still fit the contents of each individual tab. I.e. the width of the tabs would not automatically fill the available width.