G-7230 - make clear that constants in package specifications are okay

[PhilippSalvisberg]

The bad example in G-7230 uses constants. In this context it is fine to make them private. However there are other constants should be public. Here an example from my related blog post:

CREATE OR REPLACE PACKAGE const_boolean AUTHID DEFINER IS
   co_true  CONSTANT INTEGER := 1;
   co_false CONSTANT INTEGER := 0;
END const_boolean;
/

The guideline should be changed to make clear that this is good.

Furthermore the PL/SQL cop validator should be amended to ignore constant declarations in package specifications.

[PhilippSalvisberg]

I've opened the ticket PLSQLCOP-267 to fix this issue in the validator. It's not directly related to this issue. This means no need to wait for new guideline version to fix this in the validator.