feat: video discovery

[rayblair06]

🔗 Linked issue

#299

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

• Added discoverVideo functionality to discover <video> tags in pre-rendered content.
• Extended functionality of extractSitemapMetaFromHtml to extract attributes from <video> to provide required values for video sitemap(s).
• Added tests to cover new extractSitemapMetaFromHtml functionality.

Example: screenshots below show the HTML and what the expected sitemap results would be.

Considerations

• discoverVideos is enabled by default to be consistent with discoverImages option.
• Required video sitemap tags (thumbnail_loc, title, description, content_loc) will return empty string in the event there are no value provided for that attribute. Google recommended these tags are 'required'.
• src/runtime/nitro/plugins/nuxt-content.ts will search only top-level <video src="...>. I'll be honest I wasn't totally sure of this functionality I simply mimicked discoverImage. Happy to provide additional changes.

[harlan-zw]

Well that was quick! The code looks good.

I'll merge for now but I won't be available to do a release until Monday.

If you have time to update docs it would be appreciated 🙏 https://github.com/harlan-zw/nuxt-seo/blob/main/docs/content/2.sitemap/2.guides/2.images-videos.md

Thanks for the great work

[rayblair06]

Sounds great @harlan-zw! I'll send over a PR to update the docs.

[harlan-zw]

Sounds great @harlan-zw! I'll send over a PR to update the docs.

Already done 😛 Any edits welcome though