anchor.diff:  
   Example:
   \(nyxt-url 'nyxt:describe-command :value 'nyxt:describe-value)
  -=> \"about:describe-command?value=NYXT%3ADESCRIBE-VALUE\"
  +=> \"nyxt:describe-command?value=NYXT%3ADESCRIBE-VALUE\"
   
   \(parse-nyxt-url (nyxt-url 'nyxt:describe-value :value ''nyxt:*browser*))
   => NYXT:DESCRIBE-VALUE
  
positive.code:            (if (member (package-name (symbol-package symbol)) '("nyxt" "keyword")
                         :test #'string-equal)
                 (str:downcase (symbol-name symbol))
                 (str:downcase
                  (format nil "~a/~a"
                          (package-name (symbol-package symbol))
                          (symbol-name symbol))))))
      (if (gethash function-name *nyxt-url-commands*)
          (let ((params (quri:url-encode-params
                         (mapcar (lambda (pair)
  
negative.code: `parse-nyxt-url' can be repeatedly called on the same nyxt: URL, with the
  guarantee of the same result."
    (let* ((url (url url))
           (symbol (quri:uri-path url))
           (params (quri:uri-query-params url))
           (function (read-from-string (str:upcase symbol))))
      (if (gethash function *nyxt-url-commands*)
          (values function
                  (alex:mappend (lambda (pair)
  