NR percussion: Remove advice obsoleted by issue 2240

\parenthesize works fine on single notes.

Conflicts:
	Documentation/notation/percussion.itely
NR percussion: Parenthesis_engraver is available at Score level
Doc-fr: updates NR
 - percussions
 - simultaneous
Doc-es: Typo and nitpick.
Doc-es: Typos.
Doc: make real destructive code innocuous.
Doc: misplaced comments produce wrong HTML output.
Doc: clarify because a «command» is not always a lilypond command.
Revert "Doc: misplaced comments produce wrong HTML output."

This reverts commit b8f58d9897229562d1fb2dc558f8f4309005008d.
Updated snippet/new to remove spurios comments
Run makelsr
Doc-fr : typo in Vocal
Issue 3827: remove the necessity to have a \layout block in a \markup \score ...

It turns out that this is not really fixable in the backend since what
is called "layout" in the markup function definitions does not
actually correspond to \layout but rather to \paper.  Very funny.

So this is solved in the parser itself when reading a \score or
\score-lines to be used in a markup or markup list by cloning
$defaultlayout as necessary (which simulates \layout {}) whenever the
score is without an output definition.
Improve positioning of tuplet numbers for kneed beams.

In the past LilyPond always placed tuplet numbers according to the
position of a bracket, though this bracket may or may not have actually
been drawn.  This system led at times to tuplet numbers which appeared
stranded when there was a kneed beam and no visible bracket.

This patch positions the tuplet number independently of brackets and
close to the beam when the the bracket is not drawn, the beam is kneed, and
there is an appropriate beam segment to place the number against.

The side of the beam on which the number is placed is chosen by principles
derived from Gould.  The number is centered horizontally on the beam.

Collision detection is also introduced.  The number will be offset
horizontally if it is too close to an adjoining note column.  All shifts
preserve the number's vertical distance from the beam.  If the number is
too large to fit in the available horizontal space (between note columns
to either side), we use the old bracket-based positioning system.  In the
event of a collision with an accidental, the tuplet number is moved
vertically, away from the beam.

The older behavior is always available through an override of the property
`knee-to-beam' which is introduced by this patch, and set by default to true.

This patch also adds a header file, `tuplet-number.hh', and provides
a number of regression tests illustrating various features.
Update version numbers for documentation redirects
Merge remote-tracking branch 'origin/translation' into staging

Conflicts:
	Documentation/notation/percussion.itely
Added Aurelien's 100-min Ring Cycle for children

Added to introduction.itexi and tweets.xml (for pondings).
NR: 1.4.1 Replaced deprecated snippet w\ @lilypond

Issue 3801

Removed reference to snippet and added a suitable
@lilypond example.

Also removed snippet from ../snippets/new/..
NR: Removed example for alternate repeats

Since Issue 3855 it is no longer necessary to set the
timing.Measurelength when alternates begin with
incomplete measures.
Makelsr run - removed deprecated snippet

Based on Commit 637c07 - Feb 17