Sorry for the delay, here is the new patch. The \pset output will look like follow:
postgres=# \pset
Border style (border) is 1.
Target width (columns) unset.
Expanded display (expanded) is off.
Field separator (fieldsep) is "|".
Default footer (footer) is on. Output format (format) s aligned. Line style (linestyle) is ascii.
Null display (null) is "".
Locale-adjusted numeric output (numericlocale) is off.
Pager (pager) is used for long output. Record separator (recordsep) is <newline>.
Table attributes (tableattr) unset. Title (title) unset.
Tuples only (tuples_only) is off.
postgres=# \pset null # Null display (null) is "#". postgres=#
This also mean that all translation strings of those messages should be updated.
If we don't want to modify those messages, I can provide an other patch which print output as follow:
postgres=# \pset border: Border style is 1. columns: Target width unset. expanded: Expanded display is off. fieldsep: Field separator is "|". footer: Default footer is on. format: Output format is aligned. linestyle: Line style is ascii. null: Null display is "". numericlocale: Locale-adjusted numeric output is off. pager: Pager is used for long output. recordsep: Record separator is <newline>. tableattr: Table attributes unset. title: Title unset. tuples_only: Tuples only is off.
postgres=# \pset null # Null display is "#". postgres=#
I think the first output is better but it need translation work. Let me know.