added credits

src/docs/asciidoc/wiki/emoji.adoc

@@ -954,3 +954,10 @@ emoji:wheelchair[2x] [.small]`wheelchair` +
 emoji:white-flower[2x] [.small]`white-flower` +
 emoji:x[2x] [.small]`x` +
 |===
+
+
+== Credits
+
+Emoji support by link:https://github.com/twitter/twemoji[twemoji].
+
+Emoji graphics licensed under CC-BY 4.0: https://creativecommons.org/licenses/by/4.0/