bug#4136: 23.1; delete-pair

[martin rudalics]

> This is rather vague semantics.  I suggest to keep the current simple
> semantics and just to fix it with the patch I sent.

Before a quoted object your fixed version deletes the last character of
the object and the first quote character.  Handling quote or prefix
syntax characters via (delete-char 1) doesn't strike me as very clean.

martin