Standardize paths, fix path traversal

[huwr]

As per RFC-3986 5.2.4 (Remove Dot Segments), we want to remove ..s. We can use Foundation's URL.standardized features for that.

However, I am sleepy, so this may have missed something obvious.

Fixes /issues/24

[codecov]

Codecov Report

Merging #25 (779fd2c) into main (0984529) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main      #25   +/-   ##
=======================================
  Coverage   99.75%   99.75%           
=======================================
  Files          42       42           
  Lines        2002     2002           
=======================================
  Hits         1997     1997           
  Misses          5        5           

Impacted Files	Coverage Δ
FlyingFox/Sources/HTTPDecoder.swift	100.00% <100.00%> (ø)

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[stackotter]

I love the choice of branch name btw hahah. From now on I’m definitely going to call path traversals ‘naughty paths’.

[swhitty]

Looks great, a nice simple fix

[swhitty]

Looks like we found another place where CoreLibsFoundation differs from Darwin Foundation. I have updated the test to pass here, but maybe we should normalise the behaviour across all platforms.

[stackotter]

That is certainly very annoying. You would think it would be very easy for the two Foundations to have the same behaviour in that context, weird.