Add desugar rule for handle statement

[JSAbrahams]

Relevant issues

97

Summary

Desugar handle statement to a try except.

Added Tests

• [x] Modified smoke class test for handle statement.
• [x] Add tests to check that desugaring invalid handle statements results in a panic.

[codecov[bot]]

Codecov Report

Merging #106 into master will decrease coverage by 0.07%. The diff coverage is 78.82%.

@@            Coverage Diff             @@
##           master     #106      +/-   ##
==========================================
- Coverage   83.61%   83.53%   -0.08%     
==========================================
  Files          63       65       +2     
  Lines        4235     4319      +84     
==========================================
+ Hits         3541     3608      +67     
- Misses        694      711      +17

Impacted Files	Coverage Δ
src/core/construct.rs	32.07% <0%> (-1.59%)	:arrow_down:
tests/parser/invalid/error.rs	100% <100%> (ø)
src/desugar/node.rs	68.51% <70%> (+0.45%)	:arrow_up:
tests/desugar/error.rs	85.71% <85.71%> (ø)
src/core/mod.rs	72.15% <88.23%> (+1.71%)	:arrow_up:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 9ffd39e...5f77ca5. Read the comment docs.