fix: remove broken chemical formula

packages/content/markdown/posts/test post.md

@@ -161,7 +161,8 @@ $e=mc^2$ is actually $e^2=(mc^2)^2 + (pc)^2$.
 ### Block
 
 $$
-	\ce{6 CO2 + 6 H2O <=>[{photosynthesis}][{respiration}] C6H12O6 + 6 O2}
+    \text{The formula for normal distribution is} \space
+    f(x)=\frac{1}{\sigma\sqrt{2\pi}}e^{-\frac{1}{2}(\frac{x-\mu}{\sigma})^2}
 $$
 
 ## headers

packages/content/src/parseMarkdown.ts

@@ -1,5 +1,3 @@
-import "katex/contrib/mhchem" // chemical formula, https://katex.org/docs/node.html#using-mhchem-extension
-
 import remarkCalloutDirectives from "@microflash/remark-callout-directives"
 import matter from "gray-matter"
 import { JSDOM } from "jsdom"