Remove mention of http_CollectHdrSep().

So that part of the docs appear in the SYNOPSIS section.

DEFAULT is interpreted as LOWER for the HEX and URL encodings, and
is the only legal value for all other encodings.

and let that check if another function is desired.

syslog-ism "%m" being used in vsnprintf() via VSB.

That said, it would have been damn convenient of %m was also usable
in *printf(3)...

We seem to have most of it.

server.identity is not a new VCL variable.

Like $Event, $ABI has the effect of making generated docs until
the next $-directive disappear.

For out-of-tree utilities.

The corresponding symbols were already in libvarnishapi since 1.5!