feat: add leibniz formula

README.md

@@ -7,5 +7,6 @@
 | ModularInv              | 求乘法逆元【扩展欧几里得法】     | -                                                                                                                           |
 | Sqrt10                  | 求 $\sqrt{10}$【连分数】 | [resolve-sqrt-10](https://hatter.ink/static/resource/muboard/?id=resolve-sqrt-10&version=latest&full=1)                     |
 | WallisProduct           | 沃里斯乘积              | [wallis-product](https://hatter.ink/static/resource/muboard/?id=wallis-product&version=latest&full=1)                       |
+| LeibnizFormula          | $\pi$ 的莱布尼茨公式      | [leibniz-formula](https://hatter.ink/static/resource/muboard/?id=leibniz-formula&version=1)                                 |
 | EulerNumber             | 欧拉数                | [eulers-number](https://hatter.ink/static/resource/muboard/?id=eulers-number&version=latest&full=1)                         |
 | BirthdayParadox         | 生日悖论               | [birthday-paradox](https://hatter.ink/static/resource/muboard/?id=birthday-paradox&version=latest&full=1)                   |