Escape for $ in XPath 2 regexps

This comment concerns section 7.6.1 of XQuery 1.0 and XPath 2.0
Functions and Operators.

Since the regular expression syntax adds the meta-character $, there
should be a corresponding escape \$ added to the single-character
escapes (schema production [24]).

(There is already an escape for ^ because schema uses it as a
metacharacter in character groups.)

You should also urge the Schema WG to add this escape, for
consistency.  It would not break any existing schema regular
expressions.

-- Richard