replace detector resolution example (#769)

Sharp diffraction pattern and exaggerated resolution function to show a clear effect.

Non-quadratic detector and anisotropic resolution to make test sensitive for bugs in index handling.

This resolves #769 (closed).

Follow-up issues:

• #772 (closed) revise ad-hoc repair of DiffUtil::meanRelVecDiff; investigate tiny numbers in examples/scatter2d/Resolution
• #773 (closed) update hugo

enabled an automatic merge when the pipeline for e1b7e0f8 succeeds

aborted the automatic merge because source branch was updated

added 1 commit

• 18ad9581 - outcomment test

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added 1 commit

• c903e4f6 - clang-format

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merged

mentioned in commit b9a5ae1b