Update Documentation URLs

[lukewhiting]

This PR moves the majority of our deprecation notices to using short URLs and updates the URL naming scheme to be more consistent.

Instead of using the current major version number in the URL, this PR changes things so we instead use the version number the deprecation was introduced in. This rescues backporting workload and makes it clearer which URLs remain relevant.

Some URLs are placeholders at the moment while we await the new 9.0 documentation.

Here's the table of links:

Full Alias URL	Proposed New URL
https://ela.st/es-deprecation-ds-reindex	TBD
https://ela.st/es-deprecation-ds-reindex	TBD
https://ela.st/es-deprecation-7-frozen-index	https://www.elastic.co/guide/en/elasticsearch/reference/7.17/frozen-indices.html
https://ela.st/es-deprecation-9-transform-destination-index	TBD
https://ela.st/es-deprecation-9-index-version	TBD
https://ela.st/es-deprecation-9-transform-destination-index	TBD
https://ela.st/es-deprecation-9-index-version	TBD
https://ela.st/es-deprecation-7-translog-retention	https://www.elastic.co/guide/en/elasticsearch/reference/7.17/index-modules-translog.html#index-modules-translog-retention
https://ela.st/es-deprecation-7-index-data-path	https://www.elastic.co/guide/en/elasticsearch/reference/7.13/migrating-7.13.html#breaking_713_settings_deprecations
https://ela.st/es-deprecation-7-simplefs	https://www.elastic.co/guide/en/elasticsearch/reference/7.15/index-modules-store.html
https://ela.st/es-deprecation-7-data-feed-query	https://www.elastic.co/guide/en/elasticsearch/reference/7.0/breaking-changes-7.0.html#_changes_to_queries
https://ela.st/es-deprecation-7-data-feed-aggregation	https://www.elastic.co/guide/en/elasticsearch/reference/7.0/breaking-changes-7.0.html#breaking_70_aggregations_changes
https://ela.st/es-deprecation-8-model-snapshot-version	https://www.elastic.co/guide/en/elasticsearch/reference/8.17/ml-upgrade-job-model-snapshot.html
https://ela.st/es-deprecation-7-shared-data-path	https://www.elastic.co/guide/en/elasticsearch/reference/7.13/breaking-changes-7.13.html#deprecate-shared-data-path-setting
https://ela.st/es-deprecation-7-realm-prefix	https://www.elastic.co/guide/en/elasticsearch/reference/7.14/migrating-7.14.html#breaking_714_security_changes
https://ela.st/es-deprecation-7-single-node-disk-watermark	https://www.elastic.co/guide/en/elasticsearch/reference/7.14/migrating-7.14.html#breaking_714_core_deprecations
https://ela.st/es-deprecation-7-eql-enabled-setting	https://www.elastic.co/guide/en/elasticsearch/reference/7.8/breaking-changes-7.8.html#breaking_78_settings_changes
https://ela.st/es-deprecation-8-watcher-settings	#94133
https://ela.st/es-deprecation-9-tracing-apm-settings	#119926

Fixes ES-9508

[Copilot]

Pull Request Overview

This PR updates deprecation documentation URLs to use consistent short URLs and a revised versioning scheme, simplifying backports and clarifying version relevance.

• Updated URLs in deprecation notices for ML, Index, ILM policy, Data Stream, and Node checks
• Adjusted the URL naming scheme to reflect when deprecations were introduced instead of the current major version

Reviewed Changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/MlDeprecationChecker.java	Updated URLs for data feed query, aggregation, and ML model snapshot deprecations
x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/IndexDeprecationChecker.java	Replaced long upgrade URLs with short URLs for transform, index version, translog retention, shared data path, and simplefs settings
x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/IlmPolicyDeprecationChecker.java	Updated URL for frozen indices deprecation
x-pack/plugin/deprecation/src/test/java/org/elasticsearch/xpack/deprecation/IndexDeprecationCheckerTests.java	Adjusted expected URLs to match new short URL scheme for index and transform deprecations
x-pack/plugin/deprecation/src/test/java/org/elasticsearch/xpack/deprecation/DataStreamDeprecationCheckerTests.java	Updated deprecation messages and URLs for data streams using dynamic version values
x-pack/plugin/deprecation/src/test/java/org/elasticsearch/xpack/deprecation/NodeDeprecationChecksTests.java	Changed expected URLs for realm and watcher settings deprecations
x-pack/plugin/deprecation/src/test/java/org/elasticsearch/xpack/deprecation/IlmPolicyDeprecationCheckerTests.java	Updated expected URL for frozen action deprecation in ILM policies
x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/NodeDeprecationChecks.java	Revised URLs for shared data path, realm prefixes, EQL enabled, and watcher bulk settings
x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/DataStreamDeprecationChecker.java	Updated deprecation messages and URLs for data stream indices using dynamic version values

Comments suppressed due to low confidence (4)

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/MlDeprecationChecker.java:100

• Verify that the new URL for ML model snapshot deprecation correctly reflects the intended documentation; ensure it aligns with the deprecation context.

                    "https://ela.st/es-deprecation-8-model-snapshot-version",

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/IndexDeprecationChecker.java:104

• Confirm that 'https://ela.st/es-deprecation-9-transform-destination-index' is the correct target URL for the transform destination index deprecation in every occurrence.

                    "https://ela.st/es-deprecation-9-transform-destination-index",

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/NodeDeprecationChecks.java:1021

• Ensure that the new URL for the watcher bulk concurrency setting ('https://ela.st/es-deprecation-8-watcher-settings') accurately points to the documentation specific to that deprecated setting.

        String url = "https://ela.st/es-deprecation-8-watcher-settings";

x-pack/plugin/deprecation/src/test/java/org/elasticsearch/xpack/deprecation/DataStreamDeprecationCheckerTests.java:60

• Review the concatenation of Version.CURRENT.major with '0.0' in the deprecation message to ensure it produces the intended version format.

            "Old data stream with a compatibility version < " + Version.CURRENT.major + "0.0",

[gmarouli]

LGTM to me in general but I do have one question about how we treat index compatibility.

[gmarouli]

Nit: When we check the lucene compatibility for indices we hardcode version 9.0.0 but when we check it for data streams it's not version specific. I am wondering why we have different approaches in these two cases; I initially expected them to be treated in the same way.

[lukewhiting]

Yeah it's mostly a choice on my part... We own the DS check so I felt comfortable improving it but not the index one so I didn't want to go messing with the logic there too much, especially as I'm not sure what Kibana does with those messages and if it tries to parse them.

Might be being a little over cautious so happy to go back and give the index check the same treatment or, to roll this one back so it's hard coded the same as the main index check.

[gmarouli]

I see, I think we own both so if this is stopping you then I understand. I think Kibana should be ok, I do not think it parses the messages, if you have time we could double check it with them; otherwise, we can leave it as it is.

[lukewhiting]

Ahhh good stuff. I thought core owned the index deprecation notices so avoided it... Anyway I have updated those to now use a dynamic version number but was careful to make sure the messages didn't actually change their content to sidestep any kibana issues.