docs: add comments for genius behavior

README.org

@@ -94,3 +94,5 @@ The album cover fetching is similar. The corresponding function is set in ~lyric
 - =sync= - as above.
 
 The first argument is =track= because in EMMS all the required information is stored in tracks, and album data is deduced from tracks. So this package just takes a sample track in the album.
+* Troubleshooting
+I've noticed that Genius can give pages with different DOMs to different people. If you have an empty buffer instead of lyrics, please attach the =curl-cookie-jar= file to the issue. It usually resides in =.emacs.d/request=.

lyrics-fetcher-genius.el

@@ -236,6 +236,9 @@ If SYNC is non-nil, the request will be performed synchronously."
                 (let* ((html (with-temp-buffer
                                (insert data)
                                (libxml-parse-html-region (point-min) (point-max))))
+                       ;; Apparently, Genius can give different
+                       ;; responses to different people based on
+                       ;; cookies.
                        (lyrics-divs (or (dom-by-class html (rx bos "lyrics" eos))
                                         (dom-by-class html (rx bos "Lyrics__Container" (* nonl))))))
                   (funcall callback

lyrics-fetcher.el

@@ -5,7 +5,7 @@
 
 ;; Author: Korytov Pavel <thexcloud@gmail.com>
 ;; Maintainer: Korytov Pavel <thexcloud@gmail.com>
-;; Version: 0.1.2
+;; Version: 0.1.3
 ;; Package-Requires: ((emacs "27") (emms "7.5") (f "0.20.0") (request "0.3.2"))
 ;; Homepage: https://github.com/SqrtMinusOne/lyrics-fetcher.el