Rearrange sections in "Patterns"

[JanLikar]

• Move "Destructuring" after "Multiple patterns", because some of
  later sections include examples which make use of destructuring.
• Move "Ignoring bindings" after "Destructoring", because the former
  features Result<T,E> destructuring. Some of examples in later
  sections use "_" and "..", so "Ignoring bindings" must be
  positioned before them.
• Fix difficulty with binding example in patterns.md #27347 by moving "Ref and mut ref" before "Ranges" and
  "Bindings", because "Bindings" section includes a somewhat
  difficult example, which also makes use of "ref" and "mut ref"
  operators.

[rust-highfive]

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[steveklabnik]

@bors: r+ rollup

[bors]

📌 Commit c1f938d has been approved by steveklabnik

[steveklabnik]

Thank you! I agree that this ordering makes more sense.

[JanLikar]

It's still not perfect, but I think it is very hard to showcase intermediate features of Rust without also using some that were never mentioned before. It's a bit like "dependency hell" or "Chicken or the egg" paradox.

[steveklabnik]

yup, it's taken me a number of iterations over a long period of time to minimize them...