wechatMarkdown removes some formatting markers from contents

[zhongdongy]

Input

This is **bold font** text.

This is an `inline code block` example.

This is *italic font** text.

This is another _italic font_ text.

Expected output

This is **bold font** text.

This is an `inline code block` example.

This is *italic font** text.

This is another _italic font_ text.

Actual output

This is bold font text.

This is an inline code block example.

This is italic font text.

This is another italic font text.

[zhongdongy]

Currently bypassed by #3 and we might keep this issue open for tracking purpose before it got resolved.