append ‘common-lisp-snippet’ to ‘yas-snippet-dir’

This fixes #2. As described in that issue we should not push new value
to ‘yes-snippet-dirs’, because then all custom snippets go into ‘car’
directory in that list, that is, directory of Common Lisp snippets.

This commit adds Common Lisp snippets directory appending it to existing
list.

Author: mrkkrp

common-lisp-snippets.el

@@ -42,7 +42,7 @@
   "Initialize Common Lisp snippets, so Yasnippet can see them."
   (let ((dir (expand-file-name "snippets" common-lisp-snippets-root)))
     (when (boundp 'yas-snippet-dirs)
-      (add-to-list 'yas-snippet-dirs dir))
+      (add-to-list 'yas-snippet-dirs dir t))
     (yas-load-directory dir)))
 
 ;;;###autoload