Remove expander for strings in Visual D

[Rainer Schuetze]

On 26/10/2018 02:29, Michelle Long wrote:
> Strings have an expander and are treated like arrays but they don't have
> to be. The string is already shown in the value and there is the text
> viewer for them. The expander just gets in the way.

The array display can also be helpful for some lowlevel code that
iterates over the string, especially if there multi-byte characters in a
string. I don't think having the option to expand the string is too
distractive.