Update RELEASE-NOTES.md

Author: jlukic

RELEASE-NOTES.md

@@ -2,7 +2,7 @@
 
 ### Version 2.3.1 - Mar 19, 2018
 
-> **A Speical Message about Flex Modals**
+> **A Special Message about Flex Modals**
 > There will be an update shortly to resolve issues related to flex modals when using multiple modals and `detachable: false`, in order to not hold up this release, we've decided to move forward without a general solve.
 
 A general solution will most likely require branching code for IE11 which will disable flex (as IE11 doesnt correctly implement the latest spec for [absolute positioned flex containers](https://developers.google.com/web/updates/2016/06/absolute-positioned-children)).