[npmjs.com] Add syntaxs support for [!TIP] blockquotes in markdown files

[polarove]

Bear with me, I can't find anyplace else to submit this issue.

Brief:
There are several tags in markdown includes

• [!IMPORTANT]
• [!WARNING]
• [!TIP]
• [!NOTE]
• [!CAUTION]

They can be renderred into some beautiful headers, can we have this feature for each homepage of package in npmjs.com?

Related issue:

[Markdown] An option to highlight a "Note" and "Warning" using blockquote (Beta)