Return notehead with pitch in chord. Set pitch to an Abjad Pitch instance or a number.
abjad> chord = Chord([12, 14, 23], Rational(1, 4))
abjad> chordtools.get_notehead(chord, 14)
NoteHead('d', 5)
Raise MissingNoteHeadError when chord contains no notehead with pitch equal to pitch.
abjad> chord = Chord([12, 14, 23], Rational(1, 4))
abjad> chordtools.get_notehead(chord, 14)
MissingNoteHeadError
Raise ExtraNoteHeadError when chord contains more than one notehead with pitch equal to pitch.
abjad> chord = Chord([12, 12], Rational(1, 4))
abjad> chordtools.get_notehead(chord, 12)
ExtraNoteHeadError