Fix ** not matching single path segment

[michaelenger]

Fixes #488.

When we reache the ** node we're at the path segment it is going to match against. The currentIndex is incremented on line 125 which means that we're going to continue checking from the next segment over. So if we increment again before we go into the while loop we've skipped over one and will fail to match the end of the path against our pattern.

[swifter-bot]

	2 Warnings
⚠️	It seems like you've added new tests to the library. If that's the case, please update the XCTestManifests.swift file running in your terminal the command swift test --generate-linuxmain.
⚠️	If you ran the command swift test --generate-linuxmain in your terminal, please remove the line testCase(IOSafetyTests.__allTests__IOSafetyTests), from public func __allTests() -> [XCTestCaseEntry] in the bottom of the file. For more reference see #366.

	1 Message
📖	Hey, @michaelenger 👋.

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[michaelenger]

Closing this as it's clear it won't be merged.