Rename foreach_ macros to foreach_declared_ macros

[naisila]

This is prep work for successful compilation with PG17

PG17added foreach_ptr, foreach_int and foreach_oid macros
Relevant PG commit
14dd0f27d7cd56ffae9ecdbe324965073d01a9ff
postgres/postgres@14dd0f2

We already have these macros, but they are different with the
PG17 ones because our macros take a DECLARED variable, whereas
the PG16 macros declare a locally-scoped loop variable themselves.

Hence I am renaming our macros to foreach_declared_

I am separating this into its own PR since it touches many files. The main compilation PR is #7699

[codecov]

Codecov Report

Attention: Patch coverage is 97.08861% with 23 lines in your changes missing coverage. Please review.

Project coverage is 89.65%. Comparing base (15ecc37) to head (e581885).
Report is 1 commits behind head on release-13.0.

Additional details and impacted files

@@              Coverage Diff              @@
##           release-13.0    #7700   +/-   ##
=============================================
  Coverage         89.64%   89.65%           
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  Files               274      274           
  Lines             59575    59575           
  Branches           7435     7435           
=============================================
+ Hits              53407    53411    +4     
+ Misses             4036     4033    -3     
+ Partials           2132     2131    -1     

[Green-Chan]

Have you considered rewriting the code to use PG17's macros, and remove existing macros? I understand Citus should work with previous PG versions too, so this approach probably includes defining these PG17-like macros in Citus if PG_VERSION_NUM <= PG_VERSION_16

[naisila]

Have you considered rewriting the code to use PG17's macros, and remove existing macros? I understand Citus should work with previous PG versions too, so this approach probably includes defining these PG17-like macros in Citus if PG_VERSION_NUM <= PG_VERSION_16

Hey @Green-Chan please see this discussion #7651 (comment)