Test link checker with respect to hard-coded guide URLs

[kilfoyle]

TEST PR ONLY

This adds three links, one using the {security-guide} attribute, one using a hard-coded URL, and one using a hard-coded URL preceded by "link:". Let's see if the link checker complains about these.

Here's how the output renders:

I'm trying to understand the following link checking error from this build:

2024-02-22 15:27:28 EST | INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/security/current/suspicious-file-creation-in-etc-for-persistence.html contains broken links to:
-- | --
  | 2024-02-22 15:27:28 EST | INFO:build_docs:   - en/security/current/osquery-placeholder-fields.html[placeholder

Preview: https://ingest-docs_bk_947.docs-preview.app.elstc.co/guide/en/fleet/master/fleet-troubleshooting.html

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[kilfoyle]

@elasticmachine run docs-build

[kilfoyle]

Seems like the CI check is stuck, so I've relaunched it.

[kilfoyle]

The first check passed swimmingly, so let's now duplicate these links and drop them inside a markdown code block.

It builds locally, though with the {security-guide} attribute uninterpolated:

[kilfoyle]

Nice! → [1 placeholder fields]

[lcawl]

Looks like the link checker doesn't like the fourth or fifth examples:

INFO:build_docs:Bad cross-document links:
--
  | INFO:build_docs: /tmp/docsbuild/target_repo/html/en/fleet/master/fleet-troubleshooting.html contains broken links to:
  | INFO:build_docs: - en/security/current/osquery-placeholder-fields.html[4
  | INFO:build_docs: - en/security/current/osquery-placeholder-fields.html[5

I'll add one more to test a markdown-formatted link in that markdown section.

[kilfoyle]

It seems it's not fond of the markdown format either. :-(

2024-02-22 21:56:29 EST | INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/fleet/master/fleet-troubleshooting.html contains broken links to:
-- | --
  | 2024-02-22 21:56:29 EST | INFO:build_docs:   - en/security/current/osquery-placeholder-fields.html)
  | 2024-02-22 21:56:29 EST | INFO:build_docs:   - en/security/current/osquery-placeholder-fields.html[4
  | 2024-02-22 21:56:29 EST | INFO:build_docs:   - en/security/current/osquery-placeholder-fields.html[5

Shall we try just a plain URL with nothing after it, similar to the example you found?

TEST8: This investigation guide uses https://www.elastic.co/guide/en/security/current/es-ui-overview.html

(using a different link so we can see if that one fails or not)

[lcawl]

Actually I don't think it minded the markdown-formatted link, since it didn't generate an error on that one. However, because of the other errors, I can't tell what it does with that URL. Probably nothing, which might be okay.

[kilfoyle]

Oh, sorry. I thought this one en/security/current/osquery-placeholder-fields.html) was due to the markdown version. Anyhow, I'll check in again tomorrow with fresh eyes. Thanks a lot for your help!

[lcawl]

You're right, I missed seeing the additional error for the markdown-formatted links. The same failures occurred when I was doing similar fixes in elastic/security-docs#4847

[kilfoyle]

I completely missed that these links appear in codeblocks and so might not be meant to be clickable. 😊

I didn't want to lose the CI results from this PR, so here's another one that suggests that (non-clickable) links will pass CI checks as long as they're followed by whitespace: #951

[kilfoyle]

Test complete.