ha_federated::index_read_idx() and ha_federatedx::index_read_idx()
have no callers and do not override a handler method. Remove them,
and remove the sentence in the comment on each index_read() that says
index_read() calls it. Comments that describe index_read_idx() now
name index_read() or index_read_idx_map(), whichever does that read.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
ecda07c656