Handling for reserved Python keywords as JsProxy attrs. Resolves #3615. Things like `from` and `finally` are reserved keywords in Python and so `a.finally` 
is a `SyntaxError`. This automatically reroutes `a.from_` on a `JsProxy` to refer to `a.from` so it
can be used reasonably conveniently from Python.

### Checklists

- [x] Add a [CHANGELOG](https://github.com/pyodide/pyodide/blob/main/docs/project/changelog.md) entry
- [x] Add / update tests
- [x] Add new / update outdated documentation

from pytest_pyodide import run_in_pyodide


@run_in_pyodide(
    packages=[
        "msprime",
    ]
)
def test_msprime(selenium):
    import msprime
    import tskit

    # basic test
    ts = msprime.sim_ancestry(10, random_seed=42)
    ts.dump("/tmp/msprime.trees")
    ts = tskit.load("/tmp/msprime.trees")
    ts2 = msprime.sim_ancestry(10, random_seed=42)
    ts.tables.assert_equals(ts2.tables, ignore_provenance=True)

from pytest_pyodide import run_in_pyodide


@run_in_pyodide(
    packages=[
        "msprime",
    ]
)
def test_msprime(selenium):
    import msprime
    import tskit

    # basic test
    ts = msprime.sim_ancestry(10, random_seed=42)
    ts.dump("/tmp/msprime.trees")
    ts = tskit.load("/tmp/msprime.trees")
    ts2 = msprime.sim_ancestry(10, random_seed=42)
    ts.tables.assert_equals(ts2.tables, ignore_provenance=True)
