Process trailing punctuation which may be redundant
Description
The package provides commands that enable the user (or package
writer) to insert punctuation after the macro. The method is
similar to that of xspace, but goes further. The package
provides the commands \xperiod, \xcomma and \xperiodcomma,
which follow a similar procedure to that of \xspace, and insert
punctuation if and only if it is necessary.
