[PATCH] Add _PG_init to PL language handler documentation

Howdy,

This tiny doc patch adds _PG_init to the skeleton example code for a
PL. The information is quite valuable to PL authors, who might miss it
when it is described in the shared library documentation.

This patch was based off of 6e2ba96 in the git mirror and a colorized
diff can be viewed here:

http://github.com/leto/postgres/commit/a9e265a7f55a0605fb4c6135f0f689c8b89e9623

Duke

--
Jonathan "Duke" Leto
jonathan@leto.net
http://leto.net