Update {Method,UnboundMethod,Proc}#source_location signatures to match Ruby 4.1

[eregon]

• Needed for Reapply "[Feature #6012] Extend source_location for end position ruby#15580

[eregon]

This doesn't work in CRuby CI, see https://github.com/ruby/ruby/actions/runs/20595820151/job/59150151742?pr=15580
What should I do then?
Exclude the tests with tool/rbs_skip_tests?
Or rebase this on top of 3.10.0 since the failures might be caused by other changes on master?

[eregon]

From #1203 (comment)

Generally, the core library RBS definition targets the latest release of Ruby.

So if that's still the case, and it seems to be according to docs then I should use tool/rbs_skip_tests I guess.
Those docs should mention that then.

BTW these errors mention

💡You can skip this test test_each_paragraph(RBS::AST::Ruby::CommentBlockTest) by adding the name to /home/runner/work/ruby/ruby/src/tool/rbs_skip_tests

But these errors don't.

I also wonder if it's good to run RBS tests related to the core library in ruby/ruby CI since we know at least some of them will fail, so not sure there is much value.
This repo seems to test against ruby-head, not sure how that works though then given those differences.