texinfo.tex: how to tell TeX to consider a line break like @* ?

[Bruno Haible]

Hi Karl,

Using texinfo.tex from texinfo-4.13 (version 2008-04-18.10).

My .texi file contains this paragraph:

  Markus Kuhn's UTF-8 and Unicode FAQ:
  @url{http://www.cl.cam.ac.uk/~mgk25/unicode.html}

The URL cannot be broken; this is fine. But it has the effect that TeX
will render the paragraph like this, writing into the margin:

  Markus Kuhn's UTF-8 and Unicode FAQ: 
http://www.cl.cam.ac.uk/~mgk25/unicode.html

The output that TeX considers alternatively, but which gets a too bad
penalty, is this one:

  Markus         Kuhn's         UTF-8         and         Unicode         FAQ:
  http://www.cl.cam.ac.uk/~mgk25/unicode.html

Indeed, I don't want such output either. The output I would like is:

  Markus Kuhn's UTF-8 and Unicode FAQ:
  http://www.cl.cam.ac.uk/~mgk25/unicode.html

How can I achieve this output *automatically*? I know that I can add a @*
before the @url, or alternatively a @address@hidden (I'm considering only
the TeX formatting for the moment.) But this is fragile. Unlike a book, a
documentation is never finished and final. It's always subject to future
modification.

In other words, is there a way for TeX to consider to put a \hfil\break,
with a smaller penalty than the one that would apply for a \break ?

None of the commands mentioned in the texinfo documentation, section
"Break Commands", appear to satisfy the requirements.

Bruno