[O] Add a new face for org-verbatim?

[kuanyui]

Org-verbatim syntax is '=STRING=' ,but the equal symbol makes it look
not distinguishing ('=' itself looks like it seems to be a part of
STRING).  I misread them often.

So, I think maybe Org-mode can add a new face for equal symbol itself? I
mean, user can dim the face of '=' to avoid confusion.