Add fragment property to URIRef

[ottokruse]

Summary of changes

Added a property fragment to URIRef so it is easy to access the URI's fragment:

>>> URIRef("http://example.com/some/path/#some-fragment").fragment
'some-fragment'
>>> URIRef("http://example.com/some/path/").fragment
''

Why is this useful?

The non-fragment part of the URI often just serves a namespace purpose, e.g. https://brickschema.org/schema/Brick#.

Actual "things" use that namespace, and have the "thing" name as the fragment, e.g. https://brickschema.org/schema/Brick#Valve_Position_Sensor

For display purposes, it's nice to get to the "thing" name, i.e. the fragment easily.

TODO: update docs and tests. I'll do that if you deem this PR is useful.

Checklist

• Checked that there aren't other open pull requests for
  the same change.
• Added tests for any changes that have a runtime impact.
• Checked that all tests and type checking passes.
• Considered granting push permissions to the PR branch,
  so maintainers can fix minor issues and keep your PR up to date.

[nicholascar]

I'm ok with this without tests as it's just passing on an existing function from urlparse().

I try to never use hash URIs with fragments but if you do use them, I can see this might be nice.

[ghost]

yup, straightforward enough to merge.

[aucampia]

pre-commit.ci autofix

[coveralls]

Coverage increased (+0.002%) to 88.557% when pulling b87a11d on ottokruse:uriref-fragment into d263009 on RDFLib:master.

[ghost]

yup, straightforward enough to merge.

aaaand ... nice work, btw 😄

[ottokruse]

Awesome! And now, when will this be merged? And released to pip?

[aucampia]

While this is useful, it is also a bit arbitrary, as we don't have scheme, netloc, path, params or query. But I think on balance it does not really do any harm to include it, and we can just deprecate it if it does cause problems down the line.

[aucampia]

@ottokruse thanks for the PR, we plan to make the next release around the middle of July.