bad remark in compound-time-signatures.ly

[Werner LEMBERG]

Since we are now embedding most of the LSR snippets into the
documentation, the reference to a `database' in the following remark
in compound-time-signatures.ly is confusing:

  [...] (Graphic measure grouping indications can also be added; see
  the appropriate snippet in this database.)

IMHO it should be replaced with something more appropriate.


    Werner