changed deprecated range(at:) to new rangeAt

[kobeumut]

No description provided.

[9to6]

Plz merge this PR.

[tid-kijyun]

What are you using the Swift version?
It seems that it has not been changed in the latest version(4.1.2 and 3.3).

[9to6]

@tid-kijyun Sorry, it's my fault. I thought i use swift4 when I compile Kanna. But when I checked it again, It' not.
I used Kanna version 4.0, Kanna was compiled by swift 3.3.
Sorry and thank you for your replying.

[kobeumut]

Yeah i see wrong swift version that i used the project. It's version 3.3. So i changed the codes that situation. Please check new codes.

[tid-kijyun]

@kobeumut Thank you for your PR. I want to merge this PR into the master branch.
However, there are two problem remaining.

1. In Swift 3.3 for Linux version, this method has not been changed. 😞
2. Please use rebase to make one commit.

Would you please consider these and fix it?

I think that it will be like this:

#if swift(>=4.0) || os(Linux)
let range = result.range(at: at)
#else
let range = result.rangeAt(at)
#endif

---

Actually, This problem has been fixed in feature/v3.0.0 branch (for Swift 3.x).
But, I forgot the task to integrate into the master branch. Thanks to you, I remembered it.

Kanna/Sources/Kanna/CSS.swift

Lines 163 to 167 in 50b2fa6

	#if os(Linux)
	let range = result.range(at: at)
	#else
	let range = result.rangeAt(at)
	#endif

Thanks

[tid-kijyun]

Sorry for taking so long. I've just merged this PR.
I simplified the commit and corresponded to the Linux version.

Thanks for your PR.