Upgrade to Chameleon 4.6.0.

[mauritsvanrees]

We should use latest Chameleon (only possible on Python 3.9+) to avoid deprecation warnings for some changes in the ast module. In Python 3.14 these will become errors.
See chameleon PR.

Zope itself also uses some deprecated ast code in Products.PageTemplates. And z3c.pt does it as well. Maybe it needs to be fixed there first:

...Zope/src/Products/PageTemplates/engine.py:312: DeprecationWarning:
  ast.Str is deprecated and will be removed in Python 3.14;
  use ast.Constant instead
    type=ast.Str(self.type),
.../Zope/src/Products/PageTemplates/engine.py:313: DeprecationWarning:
  ast.Str is deprecated and will be removed in Python 3.14;
  use ast.Constant instead
    expression=ast.Str(self.expression),
...z3c/pt/expressions.py:178: DeprecationWarning:
  ast.Str is deprecated and will be removed in Python 3.14;
  use ast.Constant instead
    component = ast.Str(part)

At any rate the Zope tests currently fail with latest Chameleon:

Failure in test testBatchIteration (Products.PageTemplates.tests.testChameleonTalesExpressions.ChameleonTalesExpressionTests.testBatchIteration)
Traceback (most recent call last):
  File "/Users/maurits/.pyenv/versions/3.13.1/lib/python3.13/unittest/case.py", line 58, in testPartExecutor
    yield
  File "/Users/maurits/.pyenv/versions/3.13.1/lib/python3.13/unittest/case.py", line 651, in run
    self._callTestMethod(testMethod)
  File "/Users/maurits/.pyenv/versions/3.13.1/lib/python3.13/unittest/case.py", line 606, in _callTestMethod
    if method() is not None:
  File "/Users/maurits/community/plone-coredev/6.2/src/Zope/src/Products/PageTemplates/tests/testHTMLTests.py", line 177, in testBatchIteration
    self.assert_expected(self.folder.t, 'CheckBatchIteration.html')
  File "/Users/maurits/community/plone-coredev/6.2/src/Zope/src/Products/PageTemplates/tests/testHTMLTests.py", line 96, in assert_expected
    assert not t._v_errors, 'Template errors: %s' % t._v_errors
AssertionError: Template errors: ['Compilation failed', 'builtins.IndentationError: unexpected indent (85fd4b83cc53a097d3f8a169b0279653.py, line 5)']

I did not yet manage to get that generated python file and see what the source code is.

[icemac]

According to https://chameleon.readthedocs.io/en/latest/configuration.html either CHAMELEON_CACHE and/or CHAMELEON_DEBUG should do the trick to inspect the contents of that file.