Today in the `repository-s3` docs we say
> Other S3-compatible storage systems may also work with Elasticsearch,
> but these are not tested or supported.
Saying that they are explicitly not supported is a very strong
statement, implying that it is positively irresponsible to use anything
except S3 or Minio, even after extensive testing. S3-compatibility in
third-party systems has matured in recent years and users today report
success with a good number of them. In contrast, we effectively claim
support for any old NFS implementation when used with the
shared-filesystem repository.
This commit weakens this statement, removing the absolute claim of
unsupportedness and instead spelling out that the user is responsible
for ironing out any incompatibilities with the storage supplier.
6ddeaa4791