add return to ctor parameters

[WebFreak001]

only added this in algebraic.d (since that's the module I care about and found the bug in)
works around dip1000 compiler bug
in general should rather fix issues than introduce new ones

[codecov-commenter]

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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 38.68%. Comparing base (69b98a4) to head (399008b).
⚠️ Report is 4 commits behind head on master.
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Additional details and impacted files

@@           Coverage Diff           @@
##           master      #92   +/-   ##
=======================================
  Coverage   38.68%   38.68%           
=======================================
  Files          12       12           
  Lines         473      473           
=======================================
  Hits          183      183           
  Misses        290      290           

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[9il]

Looks good. However, I would like to get approval from an additional Symmetry developer. @kinke, doesn't it need to be tested on the private codebase first?

[kinke]

Unrelated, I know, but forward doesn't really make sense here, for a non-auto ref param. It always boils down to a move for non-ref params.

[kinke]

@WebFreak001: You can test this in a SIL MR by changing the mir-core selection in master.selections.json to a git+https selection to your branch here.