Rename ParameterSet required namespace from global to globals

[ad-cqc]

Renames the required top-level ParameterSet namespace global to globals (ps.globals.version, globals: in YAML).

• REQUIRED_NAMESPACES, docstrings, and docstring examples in src/schematics/parameter_set.jl
• Tests in test/test_parameter_set.jl
• Tutorial docs/src/tutorials/parameter_set.md
• CHANGELOG entry under Unreleased

It's a breaking, as ParameterSet shipped in 1.18.0. Existing YAML files/dicts using global: load without error but leave globals empty, so old PS serializations must rename the key.

Testing

ParameterSet test items pass locally (353/353).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[parrangoiz]

Given that globals is a built-in function in Python this seems like a poor choice as well. Maybe let's switch to a different name altogether?

[ad-cqc]

UPD: globals is function name, which is fine to use in dot notation. But using global name ends up with hard Python syntax error.

It's global, thus this change to plural to avoid a clash with a singular Python keyword.

[gpeairs]

I suggest sending "global" to the new key in the constructor (parameter_set.jl:52-63, the isempty(prefix) branch) with if haskey(data, "global") && !haskey(data, "globals") → use the new key and @warn … maxlog=1, so that old PS files still work.

I also have a mild preference for "design" if we're changing it (no one has to remember if it's singular or plural).