Numbered parameters

Following my PR introducing a cop for numbered parameters, @koic suggested that choosing the default style required a discussion in the style guide.

As a basis, here is what we agreed upon in our team. "Explicit" array name is not per se enforcable with a cop, so I'm not sure how it would fit in the guide.

# bad - non explicit array name
results = electric_appliance.process!
results.each { _1.taste }

# bad - multi line block
waffles.each do 
  topping = @user.toppings.max_by(&:evaluation)
  _1.spread topping
end

# bad - block can be created from method
waffles.each { _1.taste } # => waffles.each(&:taste)
waffles.each { taste(_1) } # => waffles.each(&method(:taste))

# good - explicit array name + single line block + necessity to write block
waffles.each { _1.spread(jam) }
waffles.filter { _1.baking == :well_done }

Start by reviewing this issue together with the linked PR introducing the numbered-parameters cop and its referenced discussion. Compare the proposed bad and good examples, resolve the open question about explicit array names and default style, and update the style guide once the project’s position is agreed.