Fix HTML rendering on Docs index page

[pboivin]

Hi!

This pull request is for a small fix to the 'Docs' index page:
https://nodejs.org/en/docs/

In section 'Looking for API docs of previous releases?', the block of links is currently rendered as plain text instead of HTML.

This fix changes the level of indentation of the HTML snippet within the Markdown document, from 4 spaces to 2 spaces.

Before:

After:

[fhemberger]

Thanks! Seems to be related to the metalsmith-markdown update.
(Wow, why would indentation change the rendering of HTML at all?!)

[fhemberger]

Published. Thank you!

[pboivin]

Beats me. I have grepped around the docs/ folder to compare with other HTML snippets and couldn't find any other with an indentation of 4 spaces...

Thanks for the quick reply :)

[vsemozhetbyt]

(Wow, why would indentation change the rendering of HTML at all?!)

Seems per spec:

To produce a code block in Markdown, simply indent every line of the block by at least 4 spaces or 1 tab.