"always specify initial duration within { ... }" ?

[Mark Polesky]

The implicit initial duration of a { music } block is 4
(quarter note), unless that block is preceded by a block
which ends with a different duration, even if the preceding
music block is within another \book scope included from a
different file!  The docs don't do a good job of addressing
this, and it still trips me up sometimes (like when I
copy/paste { music } blocks that don't specify durations).

Both
  LM 1.2.1 "Simple notation" and
  NR 1.2.1 "Writing rhythms"
include these two sentences:

  If the duration is omitted, it is set to the previously
  entered duration.  The default for the first note is a
  quarter note.

I think this is needlessly misleading.  In context, this
implies that the duration of the first note of a { music }
block is a quarter note, though it may be more accurate to
say "each time lilypond is invoked, the default duration for
the first note read by the parser is a quarter note."

Of course, putting that kind of language in the tutorial is
out of the question in my opinion, and I think this is a
case where its better if the user doesn't know too much.

I'd like to reword both instances of this paragraph to:

  If the duration is omitted, it is set to the previously
  entered duration.  The duration of the first note in every
  { music } block should always be specified explicitly.

Any objections?

- Mark