Improve pipeline indentation handling in UseConsistentIndentation rule

[liamjpeters]

PR Summary

Two small improvements in the UseConsistentIndentation rule's handing of pipeline indentation. Flagged in this issue and issue comment.

• Rule never finds the ends of nested pipelines, as it had a fast-return when it reached a pipeline who's end position was beyond the current tokens line. It would always find the outer/parent pipeline (which contains the nested pipeline and spans past it) and return early, empty-handed.

  This would lead to some cases of "runaway" indents.

  PR sorts the pipelines, in place, by their end line number and column number. This allows the nested pipeline to be found first (as they end before their parent pipeline).

• Rule was using a single counter to keep track of pipeline indentation and then removing it all when it found a pipeline end.

  There were some edge cases that were, even with the first issue resolved, not quite right.

  PR adds in tracking of each pipeline's indentation contribution separately.

Copilot generated (and I reviewed) a bunch of tests to cover these cases. It's really getting quite good at generating tests now 🤖

Fixes #1933

PR Checklist

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• Summarized changes
• Change is not breaking
• Make sure all .cs, .ps1 and .psm1 files have the correct copyright header
• Make sure you've added a new test if existing tests do not effectively test the code changed and/or updated documentation
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