move DECLARE_INDEX from indexing.h?

In his long bootstrap-reworking thread[1] John Naylor initially proposed
moving the DECLARE_INDEX lines from indexing.h to each of the
corresponding catalog files.  However, in the end that wasn't done;
these lines are still in indexing.h.  Is there a reason for this?
Wouldn't it make more sense to have the indexes for pg_attribute appear
in catalog/pg_attribute.h, and so forth?

I was unable to find a rebuttal of the move; maybe it was just
neglected because of fog-of-war.

[1] https://postgr.es/m/CAJVSVGWO48JbbwXkJz_yBFyGYW-M9YWxnPdxJBUosDC9ou_F0Q@mail.gmail.com


-- 
Álvaro Herrera