AW: emacs-29 a2d4cd06f45: Improve VHDL mode highlighting

[Cyril Arnould]

> Cyril, are you done discussing this, or do I need to wait some more?

I was actually hoping to get Reto's and/or your input on two

points, the first one being:

> Since this introduces changes in the vhdl-compiler type, I guess

> it would be appropriate to increment the vhdl-version number?

I've seen that on Reto's website, the latest vhdl-version number

is 3.38.4, while in the emacs repository it's at 3.38.1. I'm not

sure if this is intentional or if it simply hasn't been tracked

in emacs. If development is not intended to diverge, we could

skip ahead to 3.38.5 or 3.39.1.

The second point is that we now have two solutions for backwards

compatibility code. There's my original solution which is a

slight modification of already established backwards

compatibility code. Alternatively, there's the solution

elaborated with Mattias which should be safer but is less

tested. If using a more "experimental" solution is no problem

then we can go ahead with the new approach.