Fix the overstatement check for a design doc

You used an AI to draft a design doc for an order pipeline. It says the design "guarantees exactly-once processing", "scales linearly" and "has no single point of failure", and it has no limitations section. Before design review, your team runs a check that flags every absolute claim with nothing behind it.

An assistant wrote flag_overstated_claims(doc_lines). It is in the editor. It has a bug. Find it and fix it.

Input and output:

• doc_lines: the doc's lines. Each is written <claim>|<evidence>, where the evidence names what backs the claim, like a load test. The evidence can be empty, and a line can have no | at all.
• Return the findings as strings, in document order.

Rules the tests check:

• Split a line at its first |. The claim is the text before it and the evidence is the text after it. With no |, the whole line is the claim and the evidence is empty.
• Trim whitespace (spaces, tabs, newlines) from both ends of the claim and of the evidence.
• A claim is absolute when its lowercased text contains any of these terms: exactly-once, linearly, no single point of failure, guarantees, unlimited, always, never, infinite, zero downtime, 100%. A term counts anywhere, even inside a longer word.
• Flag an absolute claim when its trimmed evidence is empty. The finding is the trimmed claim. A line is flagged once even with several terms, and a repeated line is flagged each time.
• The doc has a limitations section when any trimmed, lowercased claim contains limitations or non-goals. That line can be flagged too.
• If the doc has no limitations section, add "missing: limitations section" as the last finding.