Review: pset autocomplete add missing options

Review for Pavel Stehule's patch in CF 2013-11:

https://commitfest.postgresql.org/action/patch_view?id=1253

Patch applies cleanly and works as intended; it's a very straightforward
patch so no surprises there.

The patch expands the range of completable items for \pset, putting
them in alphabetical order and syncs them with the list in command.c
introduced by Gilles Darold's earlier patch for \pset without any
options ( https://commitfest.postgresql.org/action/patch_view?id=1202 ).

However double-checking the options available to \pset, I see there
is also 'fieldsep_zero' and 'recordsep_zero', which are special cases
for 'fieldsep' and 'recordsep' respectively and which are therefore not
displayed separately by \pset without-any-options, but should nevertheless
be tab-completable. Modified patch attached to include these.

Regards

Ian Barwick

PS I will endeavour to review a more complex patch