Allow wildcard, but with type, in handle arms

[JSAbrahams]

Relevant issues

• Resolves #422

Summary

If wildcard identified, convert to different Python expression without as {id}. Also add extra error generation to check stage if:

• Handle does consist of case.
• Condition of arm is not expression type.

Also use let else in collection for less indentation.

Added Tests

Happy

• Handle with identifiers

[codecov[bot]]

Codecov Report

Merging #423 (f4963a6) into develop (9346f06) will decrease coverage by 0.08%. The diff coverage is 73.58%.

@@             Coverage Diff             @@
##           develop     #423      +/-   ##
===========================================
- Coverage    88.19%   88.10%   -0.09%     
===========================================
  Files          110      110              
  Lines        12042    12061      +19     
===========================================
+ Hits         10620    10626       +6     
- Misses        1422     1435      +13     

Impacted Files	Coverage Δ
src/generate/convert/mod.rs	94.79% <33.33%> (-1.88%)	:arrow_down:
src/generate/ast/node.rs	77.27% <50.00%> (-0.59%)	:arrow_down:
src/generate/convert/handle.rs	60.78% <75.00%> (+2.08%)	:arrow_up:
src/check/constrain/generate/control_flow.rs	93.45% <81.81%> (+1.07%)	:arrow_up:
src/check/constrain/generate/collection.rs	96.73% <100.00%> (-0.07%)	:arrow_down:
src/generate/ast/mod.rs	95.20% <100.00%> (+0.09%)	:arrow_up:
src/check/context/clss/mod.rs	86.52% <0.00%> (-2.13%)	:arrow_down:
... and 1 more