Please remove docs tags from snippets

[Carl Sorensen]

Dear LSR editors (Neil or Valentin, IIRC),

Please remove the docs tags from the following snippets:

Specifying context with beatGrouping

Using beatLength and beatGrouping

They will be obsolete for 2.13.4 and cause problems in making documentation.

This shows a very interesting problem.  We only have *one* LSR, which is
supposed to handle both the stable and the devel docs.  But when we change
syntax in devel, and it won't work any more, then we can't leave the docs
tag on, which, IIRC, will break makelsr.py for the stable release.  This is
not a problem, unless there is going to be an additional release of the
stable version.

Hmm -- I don't know how to fix this, but I know that I can't have those two
snippets in the docs anymore for 2.13.4.

Thanks,

Carl