More fixes for recently committed context-menu additions from bug#52973

More fixes for recently committed context-menu additions from bug#52973

* lisp/hi-lock.el (highlight-symbol-at-mouse): New defalias.
(hi-lock-face-symbol-at-mouse): Rename from hi-lock-symbol-at-mouse.
(hi-lock-context-menu): Use thing-at-mouse and middle-separator.

* lisp/man.el (Man-context-menu): Fix Man-at-mouse and use middle-separator.

* lisp/mouse.el (context-menu-functions): Remove context-menu-online-search.
Add occur-context-menu and dictionary-context-menu (bug#50552).