fbca8a7644
Currently some things are not supported for colocated tables: it's not
possible to repair a colocated table, and due to this it's also not
possible to use the tombstone_gc=repair mode on a colocated table.
Extend the documentation to explain what colocated tables are and
document these restrictions.
Fixes scylladb/scylladb#27261
Closes scylladb/scylladb#27516
(cherry picked from commit 33f7bc28da)
Closes scylladb/scylladb#27772