docs(animation): fix typo! =O

closes #1992

Author: gsans

public/docs/ts/latest/guide/animations.jade

@@ -221,7 +221,7 @@ figure.image-display
   * `'3em'`
   * `'100%'`
 
-  For most dimensinal properties we can also just define a number which is then assumed to be
+  For most dimensional properties we can also just define a number which is then assumed to be
   in pixels:
 
   * `50` is the same as saying `'50px'`