The byte-compiler recently got more fussy about quotes.
Compiling /home/jonas/.emacs.d/lib/which-key/which-key.el...
In toplevel form:
lib/which-key/which-key.el:233:2: Warning: custom-declare-variable `which-key-special-keys' docstring has wrong usage of unescaped single quotes (use \= or different quoting)
lib/which-key/which-key.el:292:2: Warning: custom-declare-variable `which-key-side-window-slot' docstring has wrong usage of unescaped single quotes (use \= or different quoting)
lib/which-key/which-key.el:292:2: Warning: custom-declare-variable `which-key-side-window-slot' docstring has wrong usage of "fancy" single quotation marks
In which-key-add-keymap-based-replacements:
lib/which-key/which-key.el:899:2: Warning: docstring has wrong usage of unescaped single quotes (use \= or different quoting)
In which-key-add-key-based-replacements:
lib/which-key/which-key.el:930:2: Warning: docstring has wrong usage of unescaped single quotes (use \= or different quoting)
The byte-compiler recently got more fussy about quotes.