Added mcdisplay section to FlatEllipse_finite_mirror component

[mads-bertelsen]

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Please describe what your PR is adding in terms of features or bugfixes:
Added mcdisplay section to FlatEllipse_finite_mirror component

The NMO component inherits from this, so it gets McDisplay too.

Closes #2289

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Development OS / boundary conditions

Please describe what OS you developed and tested your additions on, and if any special dependencies are required:
Mac OS X 14.8.7

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PR Checklist for contributing to McStas/McXtrace

For a coherent and useful contribution to McStas/McXtrace, please fill in relevant parts of the checklist:

• My contribution includes patches to an existing component file

  • I have used the mcdoc utility and rendered a reasonable documentation page for the component (please attach as screenshot in comments!)
  • I have ensured that basic use of the component is OK (e.g. an instrument using it compiles?)
  • I have used the mctest utility to test one or more instruments making use of the component (please attach mcviewtest report as screenshot in comments)
  • I have used the mccode-clangformat tool to apply the standard McCode component indentation scheme
  • I have used the mcrun --c-lint "linter" and followed advice to remove most / all warnings that are raised

• My contribution includes patches to an existing instrument file

  • I have used the mcdoc utility and rendered a reasonable documentation page for the instrument (please attach as screenshot in comments!)
  • I have used the mctest utility to test the instrument (please attach mcviewtest report as screenshot in comments)
  • I have used the mcrun --c-lint "linter" and followed advice to remove most / all warnings that are raised

• My PR is meant to fix a specific, existing issue

  • I have indicated the issue number here: [BUG]: McStas NMO (“FlatMirror…") component does not have a functional DISPLAY section #2289
  • [] I have added documentation for the fix and possible side effects

• My contribution contains something else

  • Explanation is added in free form text above or below the checklist

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[mads-bertelsen]

[mads-bertelsen]

One issue with the components using conics is that SCATTER can not be called from within their functions, so the ray traces within the components are not accurate which is a pity.

[willend]

Thanks @mads-bertelsen will have a look later today / potentially next week

[willend]

Looks good @mads-bertelsen, merging