Add support for blocks

[gustawdaniel]

Expected

$$
a + b = c
$$

should works, but I need to write $a + b = c$.

In example of mathjax

https://jsbin.com/?html,output

syntax with blocks works.

[fredericcogny]

have you tried $$a + b = c$$

it works for me and it seems to be the adopted convention: https://vuepress.github.io/en/plugins/mathjax/#conventions

I agree though that it would be nicer to allow newline after the init block marker and newline before the closing block marker.

If it works for you as well with the change above maybe you can rephrase the issue?

[ysqi]

will be auto format with newline when i write md in vscode 😢 。

and I think you should remove whitespace

/(^\s*)|(\s*$)|(^\n*)|(\n*$)/g