[BUG] Content loss in mermaid between < and >

[yingmanwumen]

Describe the bug

Text in < and > in the classDiagram of mermaid cannot be shown.
For example, std::shared_ptr<ClassA> variable would be displayed as std::shared_ptr variable.

Result from CocInfo

## versions

vim version: VIM - Vi IMproved 8.2 8023995
node version: v16.14.2
coc.nvim version: 0.0.80-0480cbd997
coc.nvim directory: /home/yingmanwumen/.vim/pack/coc.nvim/start/coc.nvim
term: dumb
platform: linux

## Log of coc.nvim

2022-04-15T19:43:00.279 INFO (pid:273813) [services] - registered service "highlight"
2022-04-15T19:43:00.774 INFO (pid:273813) [plugin] - coc.nvim 0.0.80-0480cbd997 initialized with node: v16.14.2 after 645ms
2022-04-15T19:43:05.909 INFO (pid:273813) [attach] - receive notification: runCommand [ 'markdown-preview-enhanced.openPreview' ]
2022-04-15T19:43:11.609 INFO (pid:273813) [attach] - receive notification: highlight []
2022-04-15T19:43:15.024 INFO (pid:273813) [attach] - receive notification: highlight []
2022-04-15T19:45:59.182 INFO (pid:273813) [attach] - receive notification: showInfo []

Steps to reproduce
Steps to reproduce the behavior:

1. execute vim and open a markdown file
2. write down texts like this:

```mermaid
classDiagram
class ClassA {
    std::shared_ptr<ClassB> inner
}
...

3. :CocCommand markdown-preview-enhanced.openPreview
4. See error

Expected behavior

Expected the full content in the rendered mermaid diagram.

Screenshots

Additional context
None

[weirongxu]

Look like an upstream issue.

[weirongxu]

shd101wyy/vscode-markdown-preview-enhanced#583