Mention ERC-yank feature and make it optional

CHANGELOG.org

@@ -55,6 +55,9 @@
 **** Emacs Lisp
 - Add new Spacemacs snippets =micro-state= and =new-package= (thanks to
   CestDiego)
+**** ERC
+- Use =erc-yank= on ~p~ in normal state if =gist= package is available
+  (thanks to CestDiego)
 **** Evil-snipe
 - Update configuration with last upstream changes (thanks to hlissner and
   MadAnd)

contrib/!irc/erc/README.md

@@ -26,6 +26,8 @@ Layer for [ERC IRC chat][].
   (using [erc-view-log][])
 - YouTube videos Thumbnails inline (using [erc-yt][])
 - Social Graph for ERC messages (using [erc-social-graph][])
+- ERC yank, if pasting more than 5 lines, create a gist for it. (needs to have
+  `github` layer enabled, or using `gist` package)
 
 ## Install
 

contrib/!irc/erc/extensions.el

@@ -9,4 +9,7 @@
 
 (defun erc/init-erc-yank ()
   (use-package erc-yank
-    :init (bind-key "C-y" 'erc-yank erc-mode-map)))
+    :if (configuration-layer/package-usedp 'gist)
+    :init
+    (evil-define-key 'normal erc-mode-map
+      "p" 'erc-yank)))