Try to remove the extra argument introduced in #1229

[Fuco1]

I feel since the extra argument is only passed as nil explicitly from one place (plus from within a function about word or symbol syntax), we might just add some test to the function itself, so it detects where it is and whether it should accept or not the special flag and then we can remove the extra parameter. Might make the function a bit simpler and the less logic there is regarding syntax the better, it's extremely confusing part of Emacs.