[Geany] Expose yellow wavy line in GeanyIndicators

[Filip Gruszczyński]

> However, this yellow seems a little to bright. Do you
>> have any preferences to what RGB should be used for that? Shouldn't
>
> Maybe something similar to the default string colour?

I have browsed through highlighting.c and tried to grep over the whole
code base but I can't find the RGB code for this color. Could you help
me with that?

> And it may already be incremented from a previous change.  I don't
> think it is intended for it to be incremented several times between
> releases.

I see. So only the color must be adjusted and this should be finished.

-- 
Filip Gruszczyński