[Rd] Outdated information in regex.Rd

[Mikko Korpela]

The NEWS for R-devel has the following item:

> The previously included versions of zlib, bzip2, xz and PCRE have
> been removed, so suitable external (usually system) versions are
> required (see the ‘R Installation and Administration’ manual).

Therefore I believe the following information in
'src/library/base/man/regex.Rd' is no longer valid:

> If PCRE support was compiled from the sources within R, the PCRE
> version is 8.36 as described here.

-- 
Mikko Korpela
Aalto University School of Science
Department of Computer Science