minimum-Y-extent in notation/

[Graham Percival]

Could somebody who's read the spacing docs fix these?

address@hidden:~/src/lilypond/Documentation/notation$ git
grep minimum-Y-extent
ancient.itely:      \override VerticalAxisGroup #'minimum-Y-extent = ##f
ancient.itely:      \override VerticalAxisGroup #'minimum-Y-extent = ##f
percussion.itely:       \override VerticalAxisGroup #'minimum-Y-extent = #'(-4.0
percussion.itely:    \override VerticalAxisGroup #'minimum-Y-extent = #'(-3.0 .
spacing.itely:    \override VerticalAxisGroup #'minimum-Y-extent = #'(-6 . 6)


Just change them manually, but leave the @c \version strings alone for
the moment.

Cheers,
- Graham