Update nodejs documentation

[uurien]

What does this PR do? What is the motivation?

Adds support status for nextjs framework in ASM. The support was added few months ago but the documentation is not updated.

Merge instructions

• [ ] Please merge after reviewing

Additional notes

[github-actions[bot]]

Preview links (active after the build_preview check completes)

Modified Files

• https://docs-staging.datadoghq.com/ugaitz/update-node-asm-next-support/security/application_security/enabling/compatibility/nodejs
• https://docs-staging.datadoghq.com/ugaitz/update-node-asm-next-support/security/application_security/enabling/nodejs

[simon-id]

There was still one pending comment before we were supposed ti merge it @uurien