RE: Add new functions to mark/unmark/delete all bookmarks

[Drew Adams <drew.adams@oracle.com>]

> > In Lisp comments, objects quoted 'like-this' are not
> > highlighted. Objects quoted `like-this' are. That's why the latter
> > quotation seems to be preferred for Lisp comments, IME.
> 
> What is the utility of highlighting quoted symbols in comments?

Uh, they stand out.  Lisp comments can talk about
specific functions, vars, etc.  Greatly improves
readability, IMO.

E.g., Contrast these comments in dired.el, which quote:

;; Note this can't simply be run inside function `dired-ls' as the hook
;; functions probably depend on the dired-subdir-alist to be OK.

;; We make heavy use of MATCH-ANCHORED, since the regexps don't identify the
;; file name itself.  We search for Dired defined regexps, and then use the
;; Dired defined function `dired-move-to-filename' before searching for the
;; simple regexp ".+".  It is that regexp which matches the file name.

;; Files suffixed with `completion-ignored-extensions'.

;; If a dialog is used, call `read-directory-name' so the
;; dialog code knows we want directories.  Some dialogs
;; can only select directories or files when popped up,
;; not both.  If no dialog is used, call `read-file-name'
;; because the user may want completion of file names for
;; use in a wildcard pattern.

;; Do not auto-revert when the dired buffer can be currently
;; written by the user as in `wdired-mode'.

;; Use point difference instead of `current-column', because
;; the former works when `dired-hide-details-mode' is enabled.

;; Always revert when `dir-or-list' is a cons.  Also revert
;; if `dired-directory' is a cons but `dir-or-list' is not.

with these comments, in the same file, which don't quote:

;; Inherit from font-lock-comment-delimiter-face since with min-colors 8
;; font-lock-comment-face is not colored any more.

;; If the argument was syntactically  a directory name not a file name,
;; or if it happens to name a file that is a directory,
;; convert it syntactically to a directory name.
;; The reason for checking initially-was-dirname
;; and not just file-directory-p
;; is that file-directory-p is slow over ftp.

and with this comment, which both does and doesn't quote:

;; If DIR-OR-LIST is a string and there is an existing dired buffer
;; for it, just leave buffer as it is (don't even call dired-revert).
;; This saves time especially for deep trees or with ange-ftp.
;; The user can type `g' easily, and it is more consistent with find-file.
;; But if SWITCHES are given they are probably different from the
;; buffer's old value, so call dired-sort-other, which does
;; revert the buffer.
;; Revert the buffer if DIR-OR-LIST is a cons or `dired-directory'
;; is a cons and DIR-OR-LIST is a string.
;; A pity we can't possibly do "Directory has changed - refresh? "
;; like find-file does.
;; Optional argument MODE is passed to dired-find-buffer-nocreate,
;; see there.