Postgres data type reaction has no equality operator

[lounsbrough]

Describe the bug

When using the Postgres cartridge, if you try to compare two reaction values, you get an error:

SQL Error [42883]: ERROR: could not identify an equality operator for type reaction
SQL Error [42883]: ERROR: operator is only a shell: reaction = reaction

To Reproduce

Two examples to reproduce the issue:

SELECT reaction_from_smiles('CC>>CC')
UNION 
SELECT reaction_from_smiles('CC>>CC')

SELECT CASE WHEN reaction_from_smiles('CC>>CC') = reaction_from_smiles('CC>>CC') THEN 1 ELSE 0 END

Expected behavior

It would be helpful to be able to compare equality of two reactions. This would facilitate all kinds of queries in the database which are not currently possible.

Configuration (please complete the following information):

• RDKit version: 2023.09.4
• OS: Postgres 16.2