No warning for misspelled properties.

[Thomas Morley]

Hi,

although they're misspelled, neither of the commands in the following
code returns a warning, nor does 2.16.2 (apart from the _expected_
syntax error).
Selfcompiled 2.17.22 doesn't throw an error, too.

\version "2.17.21"

{
  \override Score.RehearsalMark #'verticalll-skylinesss = #'()
  \override Score.RehearsalMark.verticalll-skylinesss = #'()
  \override Score.RehearsalMark #'horizontall-skylinesss = #'()
  \override Score.RehearsalMark.horizontall-skylinesss = #'()

  \mark \default
  R1
}


Cheers,
 Harm