docs: add component comments

[metonym]

I find @component comments to be highly useful. I actually wasn't aware it was supported by the Svelte Language Server until recently.

When visiting the documentation site, I cannot find documentation on component comments using a command + f search. Currently, component comments are only documented in the FAQs section.

This PR adds documentation for component comments to the Comments section.

[Conduitry]

My gut instinct is that, until we have more documentation of ancillary tooling on svelte.dev, that this isn't the sort of thing that should live here. It's not part of the core Svelte language, and the compiler ignores it. If this is documented somewhere else, like in the language tools repo somewhere, I could get behind having a link to that.

I know at some point we had a vision of separate tabs on the svelte.dev site for all of the different official bits of tooling (generated in some way from markdown files in individual repos), but I'm not sure whether that's still something we see happening now that we've moved away from the centralized docs API.

[benmccann]

My gut instinct is that, until we have more documentation of ancillary tooling on svelte.dev, that this isn't the sort of thing that should live here.

In my mind this is part of the Svelte spec and so it does belong here. There are a number of different tools that may have to understand this syntax. Documenting it just for a single tool doesn't seem sufficient. Those tools should probably link back to docs living here instead

[changeset-bot[bot]]

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Latest commit: 19345d29611729b8d91f44bd6eb4977a735a70fb

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[metonym]

I've rebased on master.