Fix handling Unicode East Asian Width

[kishikawakatsumi]

No description provided.

[codecov]

Codecov Report

Merging #38 into master will decrease coverage by 9.43%.
The diff coverage is 58.69%.

@@            Coverage Diff             @@
##           master      #38      +/-   ##
==========================================
- Coverage    89.2%   79.77%   -9.44%     
==========================================
  Files           8        9       +1     
  Lines        2630     3663    +1033     
  Branches       53      515     +462     
==========================================
+ Hits         2346     2922     +576     
- Misses        284      741     +457

Impacted Files	Coverage Δ
Sources/SwiftPowerAssertCore/Parser.swift	81.98% <100%> (-0.09%)	⬇️
.../SwiftPowerAssertTests/SwiftPowerAssertTests.swift	99.11% <100%> (+0.05%)	⬆️
Sources/SwiftPowerAssertCore/DisplayWidth.swift	51.74% <51.74%> (ø)
...ources/SwiftPowerAssertCore/SwiftPowerAssert.swift	81.65% <83.33%> (-0.08%)	⬇️
Sources/SwiftPowerAssertCore/Instrumentor.swift	92.71% <94.36%> (+0.1%)	⬆️

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