Adds brief overview that mostly just serves as a location for links to
other more comprehensive design documentation elsewhere in the source
tree.
Closes ES-9874
Everything was a subheading of `REST and Transport Layers` but most of
these things should be sibling headings. This commit brings the
incorrectly-nested headings up a level to fix the document structure.
Relates ES-9874
* Initial TV collapse based on TransportVersions.json
* [CI] Auto commit changes from spotless
* Fix ByteSizeValueTests.
This test had been using the version INITIAL_ELASTICSEARCH_9_0 as an example of
a version that used the older ByteSizeValue transport format. Now that no such
version exists anymore, it doesn't make sense to substitute a version that uses
the new format!
* Tips for collapsing transport versions
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Co-authored-by: elasticsearchmachine <infra-root+elasticsearchmachine@elastic.co>
This is a high-level overview of the main rebalancing components and
how they interact to move shards around the cluster, and decide where
shards should go.
Relates ES-10423
This information is more discoverable as the class-level javadocs for
`ActionListener` itself rather than hidden away in a separate Markdown
file. Also this way the links all stay up to date.
David Turner