This should now complete legacy serialization to avoid ever
changing the output content.
This removes the concept of "Default Color" from the method as
that entire concept was flawed and broke the intent of chat components.
Going to actually PR this patch to Spigot soon.
This now puts us back at a point where any data saved pre Spigot
breaking things will still save back the exact same way as before,
but new component -> legacy will now be fixed to not insert undesirable
default colors (such as black) into the legacy string, and instead use
the proper reset code.
This means you can now safety get the text from a book and
put it in chat or an entity display name without worry about black
color codes or other undesired color codes leaking into the new
context where that color doesn't make sense.
This brings chat componenent serialization to 100% accuracy so
that any text input in the legacy format, converting to comps and
then back to legacy will result in identical results.
If the user explicitly sets a color as prefix to a string, it is retained,
even if that color matches the default.
This also helps improve dealing with the empty string wrappers Bukkit creates.
A unit test has been added to verify this behavior.
This patch fixes the serialization of display names, item lores and
other things which use strings with color codes. The old implementation
deleted the color codes at the beginning of the resulting string if it
matched the default color passed to the conversion function. This
resulted in items having a black display name losing the black color
code in the beginning of the text when the item was serialized (e.g.
saving an ItemStack in a Yaml config).
Spigot has now made the issue worse and expanded the scope to more places.
