The :mod:`re` module gains a new :func:`re.prefixmatch` function as an
explicit spelling of what has to date always been known as :func:`re.match`.
:class:`re.Pattern` similary gains a :meth:`re.Pattern.prefixmatch` method.

Why? Explicit is better than implicit. Other widely used languages all use
the term "match" to mean what Python uses the term "search" for. The
unadorened "match" name in Python has been a frequent case of confusion and
coding bugs due to the inconsistency with the rest if the software industry.

We do not plan to deprecate and remove the older ``match`` name.
