refactor: consistent exception naming

[prryplatypus]

Names exceptions consistently, so they match the corresponding HTTP code message.

• Modify exceptions
• Modify uses in code
• Modify tests
• Add tests

[codecov]

Codecov Report

Merging #2420 (ac9345d) into main (2bfa65e) will decrease coverage by 0.049%.
The diff coverage is 92.857%.

@@              Coverage Diff              @@
##              main     #2420       +/-   ##
=============================================
- Coverage   87.225%   87.176%   -0.050%     
=============================================
  Files           60        60               
  Lines         5057      5061        +4     
  Branches       909       909               
=============================================
+ Hits          4411      4412        +1     
- Misses         475       477        +2     
- Partials       171       172        +1     

Impacted Files	Coverage Δ
sanic/app.py	88.571% <0.000%> (ø)
sanic/http.py	87.162% <ø> (ø)
sanic/mixins/routes.py	92.800% <50.000%> (ø)
sanic/errorpages.py	97.938% <100.000%> (ø)
sanic/exceptions.py	98.888% <100.000%> (+0.051%)	⬆️
sanic/handlers.py	95.384% <100.000%> (ø)
sanic/mixins/listeners.py	96.428% <100.000%> (ø)
sanic/models/asgi.py	100.000% <100.000%> (ø)
sanic/request.py	96.327% <100.000%> (ø)
sanic/router.py	95.789% <100.000%> (ø)
... and 1 more

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[ahopkins]

This is one of those small touches that screams of polish. Nicely done, and thanks for adding this.