The waitopen and waitconnected commands in fdbcli have no help text

The `waitopen`, `waitconnected`, `changefeed`, and `blobrange` commands in fdbcli can be accessed via the autocomplete mechanism. These commands don't seem to be documented in the help text, though. If these commands aren't intended to be hidden, then we should add documentation. If they are intended to be hidden, then we should consider making them so they can't be autocompleted.

Start by locating the fdbcli command registration and the help-text or autocomplete handling for waitopen, waitconnected, changefeed, and blobrange. Determine whether these commands are intended to be public or hidden, then document them or prevent their autocomplete exposure accordingly. Verify both help output and autocomplete behavior.

Written by the indexing model from the issue text.