Noticed that on https://docs-staging.couchbase.com/server/current/guides/updating-data.html
the 3rd set of tabs don't synchronise, because `cbc-subdoc` is a
different string than `cbc`

This commit sets them all in the same "sync group" so they match for
e.g. .NET, Java, etc.

(cbc and cbc-subdoc still won't synchronize though.
That doesn't seem to be customizable from https://github.com/asciidoctor/asciidoctor-tabs#tabs-sync
Consider rewording both to `cbc` or `CLI` or similar if that would be
desirable.)

remove `tab-sync-group` parameter, and instead rename all of `cbc` and
`cbc-subdoc` to `CLI` so that they inherit the useful default behaviour.