The doc about DDL statements claims that an `ALTER KEYSPACE` will fail
in the presence of an ongoing global topology operation.
This limitation was specifically referring to RF changes, which Scylla
implements as global topology requests (`keyspace_rf_change`), and it
was true when it was first introduced (1b913dd880) because there was
no global topology request queue at that time, so only one ongoing
global request was allowed in the cluster.
This limitation was lifted with the introduction of the global topology
request queue (6489308ebc), and it was re-introduced again very
recently (2e7ba1f8ce) in a slightly different form; it now applies only
to RF changes (not to any request type) and only those that affect the
same keyspace. None of these two changes were ever reflected in the doc.
Synchronize the doc with the current state.
Fixes#27776.
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
Closesscylladb/scylladb#27786
20ff2fcc18