proposal: unescape_text function

Hi

There is one user request for unescape function in core.

https://stackoverflow.com/questions/20124393/convert-escaped-unicode-character-back-to-actual-character-in-postgresql/20125412?noredirect=1#comment110502526_20125412

This request is about possibility that we do with string literal via
functional interface instead string literals only

I wrote plpgsql function, but built in function can be simpler:

CREATE OR REPLACE FUNCTION public.unescape(text, text)
RETURNS text
LANGUAGE plpgsql
AS $function$
DECLARE result text;
BEGIN
EXECUTE format('SELECT U&%s UESCAPE %s',
quote_literal(replace($1, '\u','^')),
quote_literal($2)) INTO result;
RETURN result;
END;
$function$

postgres=# select unescape('Odpov\u011Bdn\u00E1 osoba','^');
unescape -----------------
Odpovědná osoba(1 row)

What do you think about this?

Regards

Pavel