Add MathIntegral class

src/file/paragraph/math/math-component.ts

@@ -3,6 +3,7 @@ import { MathFraction } from "./fraction";
 import { MathFunction } from "./function";
 import { MathRun } from "./math-run";
 import { MathSum } from "./n-ary";
+import { MathIntegral } from "./n-ary";
 import { MathRadical } from "./radical";
 import { MathSubScript, MathSubSuperScript, MathSuperScript } from "./script";
 
@@ -10,6 +11,7 @@ export type MathComponent =
     | MathRun
     | MathFraction
     | MathSum
+    | MathIntegral
     | MathSuperScript
     | MathSubScript
     | MathSubSuperScript