[Bug fix] Fix batch information with remove_nodes/edges applied

[mufeili]

Description

This PR updates batch information in remove_nodes and remove_edges as reported in #2310 .

Checklist

Please feel free to remove inapplicable items for your PR.

• The PR title starts with [$CATEGORY] (such as [NN], [Model], [Doc], [Feature]])
• Changes are complete (i.e. I finished coding on this PR)
• All changes have test coverage
• Code is well-documented
• To the my best knowledge, examples are either not affected by this change,
  or have been fixed to be compatible with this change
• Related issue is referred in this PR
• If the PR is for a new model/paper, I've updated the example index here.

Changes

[dgl-bot]

To trigger regression tests:

• @dgl-bot run [instance-type] [which tests] [compare-with-branch];
  For example: @dgl-bot run g4dn.4xlarge all dmlc/master or @dgl-bot run c5.9xlarge kernel,api dmlc/master

[BarclayII]

Awesome! Could you update the docstrings for both functions? Looks like it is no longer discarding the batch information. And preferably the examples.

[mufeili]

Awesome! Could you update the docstrings for both functions? Looks like it is no longer discarding the batch information. And preferably the examples.

Thanks for the doc update!