Enhancement request: make-markup-command cleanup and docs

[David Kastrup]

The current state of make-markup-command is less than satisfactory since
make-markup-command and make-builtin-markup-command have different
syntaxes and semantics, making the latter an "insider" command that
complicates the transition from advanced user to Lilypond contributor.

There has been work done on unifying the syntax at
<URL:http://codereview.appspot.com/160048>.  The last changes of those
patch sets have eliminated make-builtin-markup-command completely, and
one has been adding a command line option that stops indexing for
make-builtin-markup-command (and the respective markup list command)
completely.  The latter will make only sense if the effect of this
option is made to extend to further commands not related to markup.

So there remains a technical decision pending about the accepted scope
of the proposed changes (from none at all to the last change set).  This
decision needs to be done by somebody with commit privileges and the
required authority.

Once this has been done, the changed (or unchanged) state needs further
documentation in the CG (the in-code documentation for all variants
appears par for the course to me).

If the decision is "no change at all", the patch set at
<URL:http://codereview.appspot.com/157133> improves the CG
documentation.  It also forms an excellent starting point if the
decision is to incorporate more of the first-mentioned patch, or
otherwise change the commands of make-markup flavor.

With the mentioned sources of input, the improvement of the
contributor's guide would appear to be a task at frog level once a
decision about the scope of code changes has been made.

-- 
David Kastrup