A macro for shortening which-key descriptions

my-wk-abbrev.el

(defmacro my/wk-abbrev (prefixstr &optional prefixabbrev mode)
  "Remove PREFIXSTR from which-key descriptions.
Or, with PREFIXABBREV, replace it.  Optionally, condition
replacement on the value of MODE.  This should typically be used
in the `:config' block of the package that uses the prefix.  An
`eval-after-load' is included, to ensure that which-key will have
loaded before adding to `which-key-replacement-alist'."
  (let ((wkabbfuncsym (intern
                       (concat "my-wk-" prefixstr "-abbreviator")))
        (rx (concat "^\\(\\[[ X]\\] \\|\\)" prefixstr "-")))
    `(eval-after-load 'init
       (quote
        (setq which-key-replacement-alist
              (append
               which-key-replacement-alist
               (list
                (quote
                 ,(cons (cons nil rx)
                        (fset wkabbfuncsym
                              (lambda (wkcons)
                                (let ((inkey (car wkcons))
                                      (indesc (cdr wkcons)))
                                  (if (and mode
                                           (not (eval mode)))
                                      wkcons
                                    (cons
                                     inkey
                                     (replace-regexp-in-string
                                      rx (if prefixabbrev
                                             (concat "\\1"
                                                     prefixabbrev "-")
                                           "\\1")
                                      indesc)))))))))))))))

Example usage:

(use-package gnus
  ;; stuff here
  :config
  (my/wk-abbrev "gnus-agent"   "Ga")
  (my/wk-abbrev "gnus-server"  "Gs")
  (my/wk-abbrev "gnus-topic"   "GT")
  (my/wk-abbrev "gnus-group"   "GG")
  (my/wk-abbrev "gnus-article" "GA")
  (my/wk-abbrev "gnus-summary" "GS")
  (my/wk-abbrev "gnus-browse"  "GB"))