website: remove fixed width in code blocks of Mac Os X page
The text was cut off too soon and way before the end of the
container width.
This was problematic especially on browsers which does not display
(Android browsers) or hide after a few seconds (Safari, Epiphany)
the horizontal scrollbar, unless you hover or swipe on that area.
As reported here:
https://lists.gnu.org/archive/html/bug-lilypond/2018-07/msg00017.html
Diff:
Passes make, make check and a full make doc.
Patch on countdown for July 13th
Patch counted down - please push
pushed as c803cafd3c6c755bbb3ee05db11231273650c4c1