workspace command: extract an expression to a variable

[NJichev]

A workspace command that extracts an expression to a variable.

Example:

defmodule Example do
  def run(argument) do
    DoSomeOtherThing.run(String.split(argument, "\n"))
  end
end

Hovering the String.split expression and running the workspace command should result in something like this:

defmodule Example do
  def run(argument) do
    var = String.split(argument, "\n")
    DoSomeOtherThing.run(var)
  end
end