gnu: Add emacs-elisp-demos.

* gnu/packages/emacs-xyz.scm (emacs-elisp-demos): New variable.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu/packages/emacs-xyz.scm

@@ -2797,6 +2797,32 @@ boundaries defined by syntax highlighting.")
 for Flow files.")
       (license license:gpl3+))))
 
+(define-public emacs-elisp-demos
+  (let ((commit "4c1fbc392668662890b685ab297e950259227e06")
+        (version "0.1")
+        (revision "1"))
+    (package
+      (name "emacs-elisp-demos")
+      (version (git-version version revision commit))
+      (source
+       (origin
+         (method git-fetch)
+         (uri (git-reference
+               (url "https://github.com/xuchunyang/elisp-demos")
+               (commit commit)))
+         (file-name (git-file-name name version))
+         (sha256
+          (base32
+           "01cbkmjgmzxdf02w9xgbf4bhnx1mh53vvpkri13yxfksym5zizp4"))))
+      (build-system emacs-build-system)
+      (arguments '(#:include '("\\.el$" "\\.org$")))
+      (home-page "https://github.com/xuchunyang/elisp-demos/")
+      (synopsis "Enhance @code{*Help*} buffers with additional examples")
+      (description
+       "This package injects example uses of Elisp functions into their
+respective @code{*Help*} buffers.")
+      (license license:gpl3+))))
+
 (define-public emacs-ob-ipython
   (package
     (name "emacs-ob-ipython")