Merge Reduce Into Instead Of Loop rule

[snofla]

Adds an idiomatic rule that suggests using reduce(into:) when a for .. in loop is encountered that references a collection variable (of type Array, Set or Dictionary).

The canonical example is:

            var result: [SomeType] = []
            for eachN in someSequence {
                ↓result[someIndex] = eachN
            }