Use non-deprecated pyparsing methods

[rafguns]

Summary of changes

This PR fixes #3361 by changing the deprecated methods from pyparsing to the PEP8-compliant, non-deprecated ones.

These methods are available since pyparsing 3.0.0. Since rdflib requires pyparsing >=3.2.0,<4, this change is backwards compatible.

Checklist

• Checked that there aren't other open pull requests for
  the same change.
• Checked that all tests and type checking passes.
  7612 passed, 591 skipped, 330 xfailed, 36 xpassed, 36000 warnings in 121.93s (0:02:01)
• Considered granting push permissions to the PR branch,
  so maintainers can fix minor issues and keep your PR up to date.

[edmondchuc]

I've updated the PR to preserve handling of empty solutions in 70fe2f7.

[edmondchuc]

I've rebased the commits onto 7.x and updated the target branch, assuming the change would be non-breaking.

However, I’m not sure the compatibility claim holds:

These methods are available since pyparsing 3.0.0. Since rdflib requires pyparsing >=3.2.0,<4, this change is backwards compatible.

The failing CI check ensures all tests pass on the minimum supported Python runtime and dependency versions, which resolves pyparsing to version 2.1.0. With that version, we're seeing multiple test failures due to import errors.

This suggests the change is not backwards compatible and may require either:

• Bumping the minimum supported version of pyparsing
• Adding guarded imports for different major versions of pyparsing

[edmondchuc]

I've added a pyparsing v2 and v3 import compat layer in 59f585c.