enhancement of notes and examples in ref-del

There has been some discussion of the relationship between tei:del and tei:gap in recent years, and although I think Council is in agreement that, for example, an erasure that cannot be read should be tagged as <del><gap/></del> (rather than *<gap reason="deleted"/> [1]), even some members of Council and/or those involved in an in-depth discussion of this topic in Galway in 2008 have not been able to reconstruct this decision clearly.

[1] tei:gap and tei:del are different kinds of intervention in the text: the former is purely descriptive, "I cannot, or have chosen not to, transcribe the text here"; the latter is interpretive, "an original or historical scribe deliberately chose to erase or obscure this text". One might choose to say one or the other or both about a given span of text.

I suggest:

(a) adding an example with del containing a gap, showing this usage explicitly (and perhaps another example under subst, showing a substitution where the original text can no longer be read);

(b) simplifying the prose in the note (currently: "The text deleted must be at least partially legible, in order for the encoder to be able to transcribe it. Illegible text within a deletion may be marked using the gap tag to signal that text is present but has not been transcribed. Attributes on the gap element may be used to indicate how much text is omitted, the reason for omitting it, etc.") to make it explicit that del and gap perform different levels of function;

(c) adding to the final note, (currently: "The del tag should not be used for deletions made by editors or encoders. In these cases, either the corr tag or the gap tag should be used.") the element tei:surplus, which is also a form of editorial deletion...

(I'm happy to make these changes if nobody objects.)