Fix mispelling of 'initial'. (see #1879)

Author: dpvc

unpacked/jax/element/mml/jax.js

@@ -78,7 +78,7 @@ MathJax.ElementJax.mml.Augment({
     SANSSERIFITALIC: "sans-serif-italic",
     SANSSERIFBOLDITALIC: "sans-serif-bold-italic",
     MONOSPACE: "monospace",
-    INITIAL: "inital",
+    INITIAL: "initial",
     TAILED: "tailed",
     LOOPED: "looped",
     STRETCHED: "stretched",