Iteration chapter improvement

[AptRoApt]

Strings concatenation is a great topic to learn through TDD, but this topic is not covered in this chapter.

Strings in Go are immutable, so memory reallocates on every change of a string. We can demonstrate this with an example by benchmarking and show a solution: strings.Builder from the strings package.

To do this we can:

• Add benchmarking before the refactoring stage and run it.
• Provide a short explanation about strings in Go, explaining the purpose of using strings.Builder.
• Add strings.Builder in the refactor stage. The final function will look like:

  const repeatCount = 5
  
  func Repeat(character string) string {
     var sb strings.Builder // do not forget to import "strings"
     for i := 0; i < repeatCount; i++ {
         sb.WriteString(character)
     }
     return sb.String()
  }

• Launch becnhmarking after refactoring

I can make a pull request with this changes, if you want.

[AptRoApt]

I think that work with strings can be discussed after the chapter on arrays and slices. This section can cover not only strings.Builder, but also runes, bytes, and work with UTF-8.

[quii]

Great idea! Go for it