[Feature] Prefixes 3/n: linear combinations of prefixes

[olets]

Issue for documentation/findability.

• For discussion, see #114

See also

• #134
• #135

This feature is current a candidate for v6.

• Scalar and glob prefixes can be strung together

After

# .zshrc
the_scalar_prefixes_array_name_tbd+=( 'xyz ' )
the_glob_prefixes_array_name_tbd=( '?.' )

% abbr a=bcd
% e.xyz sudo a[SPACE] # expands to `e.xyz sudo bcd`
% xyz e.sudo a[SPACE] # expands to `xyz e.sudo bcd`
% xyz sudo e.a[SPACE] # expands to `xyz sudo e.bcd`