typo "normnal" in MathML attribute

Line 133 in MathJax-src/ts/core/MmlTree/OperatorDictionary.ts:

  [0x20000, 0x2FA1F, TEXCLASS.ORD, 'mi', 'normnal'], // CJK Unified Ideographs Ext. B (through) CJK Sompatibility Ideographs Supp.

'normnal' should be 'normal'.

Test code

console.log(String.fromCodePoint(0x20000,0x20001,0x20002));

Output: "𠀀𠀁𠀂"

Using these characters in MathJax causes error:

<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mi mathvariant="normnal">&#x20000;</mi>
  <mi mathvariant="normnal">&#x20001;</mi>
  <mi mathvariant="normnal">&#x20002;</mi>
</math>

After manually correcting the typo, these characters can be displayed.