[tei-council] [TEI-L] ptr definition

[Syd Bauman]

So, we're up against a schema-problem. There was significant
discussion during which it was suggested that our next release should
contain *no* schema changes, and although no definitive decision was
reached, it seems that many are operating under that assumption.

However, Torsten Schassan's colleague Thomas Stäcker pointed out a
discrepancy in the definition of <ptr>, which I would say is the
result of an error: since one of either target= or cRef= is supposed
to be required, the usage= of each should be "req", but that of	cRef=
is "opt", probably due to cut-and-paste error.

I"ve made this change and tested it, but it does make a teeny change
to the schema: a <ptr> element with neither target= nor cRef=, which
is currently valid would no longer be.

I'm willing to consider this a corrigible error and fix it, but y'all
may feel otherwise.