Performance issues during loading the template

[Spasenie-Brest]

I have dozen template and hundreds calls of Sorcery to generate the code, some of templates execute slowly and I try to find the issue. What I found, 150lines template spends 2+ sec to be loaded, after research I found an issue:

self.lines = zip(1..., templateString.components(separatedBy: .newlines)).compactMap { index, line in
    guard !line.isEmpty,
      let range = templateString.range(of: line) else { return nil }
    return (content: line, number: UInt(index), range)
  }

Range(of) is not light operations, it scans origin text from the beginning on each step to find the current line.
I think we can improve it, as range(of:) does have additional param searchRange: Range<Self.Index>? = nil

So we can remember previous found range and use it to set searchRange

[Spasenie-Brest]

@krzysztofzablocki @djbe