Use style instead of colours for the completion list

[gnodet]

No description provided.

[gnodet]

The style strings should be final and not changed after being converted to a style.
So instead of

        if (menuList) {
            return AttributedStyle.DEFAULT.background(getCompletionListBackgroundColor());
        }
        return AttributedStyle.DEFAULT.backgroundDefault();

I think we should duplicate the styles names and have COMPLETION_STYLE_LIST_GROUP in addition of COMPLETION_STYLE_GROUP for example.

@mattirn Thoughts ?

[mattirn]

Sure, the choice of colour as integer is bad especially if you are going to add support for true colour for the rest I think I have just modified the existing implementation.

I do not know what we can exactly set using style strings and how...
For example if we can define both foreground and background in a style then we can duplicate all the styles that we use inside menu list.
On the other hand if style can define only foreground or background colour then I think we need to duplicate only menu list background colour.

[gnodet]

Fwiw, the styles are the ansi representation of whatever the terminal support (foreground, background, bold, blink, crossed out, italic, underling...). So you can do whatever you want, the problem is that it's not really intuitive.
I'll first add some javadoc, but maybe we could find something more human readable than a list of integers... Ideally, we should leverage the StyleResolver.

[mattirn]

Not tested much but seems to work... mattirn@63b5c11

[gnodet]

I have something that leverages the StyleResolver, I'll try to push it tomorrow, but it's currently merged with the color support, so I need to split those...

[mattirn]

About human friendly styles also the latest nanorc format is quite good

[style1,style2,...,stylen,][foreground][,background]

where stylei are bold, inverse, italic, underline,... . foreground and background are colours. Everything in style string is optional. Nano.java#L1822-L1837