[Emacs 27.1] Comment and delimiter highlighting

[Marcus Harnisch]

Hi all

What determines the assignment of faces to comment delimiters and 
comment text? Syntax table or variables such as ‘comment-start’, 
‘comment-end’, etc.

The reason I am asking is that in ‘verilog-mode’ block comment enders 
are not highlighted properly:

* Set ‘font-lock-comment-face’ and ‘font-lock-comment-delimiter-face’ to
  reasonably distinguishable colours.

* Create buffer and enable verilog-mode.

* Enter this text:

/****** ****
 ***** sdhfghg
 **** ****/

* Observe that the trailing delimiter is not assigned the expected face.
  Alternatively use ‘M-x describe-char’ to see details.

There is a second issue that I noticed when comparing with a C file,
since both languages share the same comment syntax: The asterisks
immediately following the comment start delimiter are also assigned
‘font-lock-comment-delimiter-face’, even though they are not actually
part of the delimiter. Note that highlighting of asterisks preceding
the comment end delimiter does not follow the same logic (symmetry).

Cheers,
Marcus