- mention vmod_std(7)
- HEADER is released and used by vmod_std(7) so put it in its own line.
  The explanation is still needed though.
- for consistency replace leading tabs with spaces
- *fallback* are not strings so avoid mentioning the type
- use ascii characters in vmod_std(7)

And a few style changes from me to vmod_std.rst

Requested by: Federico G. Schwindt <fgsch@lodoss.net>

Reduce stacksize to 32k.

Fix previous change to not madly leak memory.

activity.

Consequent Constification

with allocating its own objcores.

When WRW is used to send stuff to the backend 'req->t_resp' is not
an appropriate base for the timeouts.

We now have:
	VSL() -> send directly to global VSL buffer
	VSLb() -> send to buffered VSL
	VSLbt() -> send txt to buffered VSL

Fixes #1056