Extra-long word durations

[Geoff Horton]

Every now and then, assigning durations to syllables really is easier
than \lyricsto. I was trying it with long-duration notes and ran into
a problem--\breve is not interpreted as a duration in Lyrics context.
Given the definition of a word (anything up until the next space or
digit), it's easy to understand why this is so, but there doesn't
appear to be a useful way to achieve the same effect, nor is it
explicit in the docs that this won't work. (I wasn't sure whether to
call this a bug and send it to the bug list or to send it here. You
see which won.)

Geoff