希腊字母：LaTex转Markdown

测试效果如下：

No. letter latex md letter latex md
1 $\alpha$ \alpha \alpha A \Alpha A
2 $\beta$ \beta \beta B \Beta B
3 $\gamma$ \gamma \gamma $\Gamma$ \Gamma \Gamma
4 $\delta$ \delta \delta $\Delta$ \Delta \Delta
5 $\epsilon$ \epsilon \epsilon E \Epsilon E
6 $\zeta$ \zeta \zeta Z \Zeta Z
7 $\eta$ \eta \eta H \Eta H
8 $\theta$ \theta \theta $\Theta$ \Theta \Theta
9 $\iota$ \iota \iota I \Iota I
10 $\kappa$ \kappa \kappa K \Kappa K
11 $\lambda$ \lambda \lambda $\Lambda$ \Lambda \Lambda
12 $\mu$ \mu \mu M \Mu M
13 $\nu$ \nu \nu N \Nu N
14 $\xi$ \xi \xi $\Xi$ \Xi \Xi
15 $\omicron$ \o \omicron O \O O
16 $\pi$ \pi \pi $\Pi$ \Pi \Pi
17 $\rho$ \rho \rho P \Rho P
18 $\sigma$ \sigma \sigma $\Sigma$ \Sigma \Sigma
19 $\tau$ \tau \tau T \Tau T
20 $\upsilon$ \upsilon \upsilon $\Upsilon$ \Upsilon \Upsilon
21 $\phi$ \phi \phi $\Phi$ \Phi \Phi
22 $\chi$ \chi \chi X \Chi X
23 $\psi$ \psi \psi $\Psi$ \Psi \Psi
24 $\omega$ \omega \omega $\Omega$ \Omega \Omega