\alias documentation issues

[Werner LEMBERG]

Looking at, say, PianoStaff node in lilypond-internals.info, I see
this:

  Just like `GrandStaff' but with a forced distance between the
  staves, so cross staff beaming and slurring can be used.

     This context is also known as:           <--

     GrandStaff

The marked line is very misleading IMHO.  I suggest to rephrase it to
something like this:

    This context also accepts commands for the following context:



       Werner