tweak(web): remove M-/ keybind

As brought up in #7866, M-/ is bound to dabbrev-expand by default. Also,
a `M-;` keybind already exists on web-mode-map for commenting (and is
the vanilla default for commenting in other modes), so I'm removing this
redundant keybind.

Close: #7866
Co-authored-by: kuba-orlik <kuba-orlik@users.noreply.github.com>

modules/lang/web/+html.el

@@ -142,7 +142,6 @@
             "p" #'web-mode-tag-previous
             "s" #'web-mode-tag-select))
 
-        :g  "M-/" #'web-mode-comment-or-uncomment
         :i  "SPC" #'self-insert-command
         :n  "za"  #'web-mode-fold-or-unfold
         :nv "]a"  #'web-mode-attribute-next