bug#41852: 27.0.50; text-scale commands don't scale header of tabulated-list-mode

[Drew Adams]

> Thanks, I changed the text as follows:
> 
> *** text-scale-mode can now adjust font size of the 'header-line' face.
> When the new buffer local variable 'text-scale-mode-header-line' is
> non-nil, 'text-scale-adjust' will also change the text height of the
> 'header-line' face.  This will affect any face that inherits from it.
> 
> This feature is useful for major modes that arrange their display in a
> tabular form below the header-line.  It is enabled by default in
> 'tabulated-list-mode' and its derived modes (such as the modes used by
> 'list-packages', 'list-buffers' and 'list-bookmarks).

LGTM; thx.

I'd suggest removing the text in parentheses.
NEWS items should generally be limited to what's new,
without additional explanation (unless it's important).