Refine workaround for S3 repo analysis known issue (#138000)

A multi-node cluster will run contended register operations even with
`?register_operation_count=1`. This commit refines the workaround in the
known issue docs to avoid this.

Author: DaveCTurner

docs/release-notes/known-issues.md

@@ -89,4 +89,4 @@ This issue will be fixed in a future patch release (see [PR #126990](https://git
     * switching the order of the grouping keys (eg. `STATS ... BY keyword2, keyword1`, if the `keyword2` has a lower cardinality)
     * reducing the grouping key cardinality, by filtering out values before STATS
 
-* Repository analyses of snapshot repositories based on AWS S3 include some checks that the APIs which relate to multipart uploads have linearizable (strongly-consistent) semantics, based on guarantees offered by representatives from AWS on this subject. Further investigation has determined that these guarantees do not hold under all conditions as previously claimed. If you are analyzing a snapshot repository based on AWS S3 using an affected version of {{es}} and you encounter a failure related to linearizable register operations, you may work around the issue and suppress these checks by setting the query parameter `?register_operation_count=1`. This issue currently affects all supported versions of {{es}}. The plan to address it is described in [#137197](https://github.com/elastic/elasticsearch/issues/137197).
+* Repository analyses of snapshot repositories based on AWS S3 include some checks that the APIs which relate to multipart uploads have linearizable (strongly-consistent) semantics, based on guarantees offered by representatives from AWS on this subject. Further investigation has determined that these guarantees do not hold under all conditions as previously claimed. If you are analyzing a snapshot repository based on AWS S3 using an affected version of {{es}} and you encounter a failure related to linearizable register operations, you may work around the issue and suppress these checks by setting the query parameter `?register_operation_count=1` and running the analysis using a one-node cluster. This issue currently affects all supported versions of {{es}}. The plan to address it is described in [#137197](https://github.com/elastic/elasticsearch/issues/137197).