docs(external): fix enrichment_table and secret docs

[titaneric]

Summary

I try to fix the issue mentioned in #22234, and I also find the similar change is needed in enrichment_table when I dive deep into the document.

I find the secret is not a simple enum, and it's more like a classic Rust enum which may have different optional fields.
Listened the hint by @pront, I find the kind field is optional field when type is counter in log_to_metrics transform, which is similar to our case.

The log_to_metrics docs insert a optional relevant_when field to let the reader knows that this is a optional field in certain case. I try to insert the same notice to both enrichment_table and secret.

Please note that there are some big change in the PR. At first, I put all of the type descriptions above, and try to merge them into concise one. Secondly, I would merge the optional field description as well when there are conflicted name (path) for different type.

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

How did you test this PR?

make run-production-site-locally

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the "no-changelog" label to this PR.

Checklist

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References

Closes: #22234

It looks strange in this PR, but I think a picture worths thousands of world.

Secret description:

Secret type:

Secret optional fields:

[pront]

Thank you @titaneric, I will take a look.

AFAIK, this was edited manually right? Please also see this comment thread: #21348 (comment)

[titaneric]

I have read the issue thread. Yes, I edit this document manually since I am not sure how to generate the CUE document from Rust code. I could dig deeper and try to help if some hint is given.

[pront]

Thank you @titaneric, this is a great improvement. Hopefully we will get to the bottom of this #22319 (comment) as well in the future.

[pront]

Let's also wait for @vectordotdev/documentation to take a look