#48 showproc fails for procs with strange args

[Andreas Leitgeb]

Arguments without default are deprived of one
list-level:

% proc foo {{{bad thing}}} { return ${bad thing} }
% showproc foo
proc foo {{bad thing}} { return ${bad thing} }

Suggested patch:
- lappend nargs $varg
+ lappend nargs [list $varg]

- AvL