rubocop/no_fileutils_rmrf: Discourage Pathname#rmtree too

- This [seems to be](https://ruby-doc.org/3.3.4/exts/pathname/Pathname.html#method-i-rmtree)
  equivalent to `FileUtils#rm_r`, so replace it with that.

Library/Homebrew/rubocops/no_fileutils_rmrf.rb

@@ -4,26 +4,32 @@
 module RuboCop
  module Cop
  module Homebrew
- # This cop checks for the use of `FileUtils.rm_f`, `FileUtils.rm_rf`, or `FileUtils.rmtree`
- # and recommends the non-`f` versions.
+ # This cop checks for the use of `FileUtils.rm_f`, `FileUtils.rm_rf`, or `{FileUtils,Pathname}.rmtree`
+ # and recommends the safer versions.
  class NoFileutilsRmrf < Base
  extend AutoCorrector
 
- MSG = "Use `FileUtils.rm`, `FileUtils.rm_r` instead of `FileUtils.rm_rf`, `FileUtils.rm_f`, or `FileUtils.rmtree`."
+ MSG = "Use `FileUtils.rm` or `FileUtils.rm_r` instead of `FileUtils.rm_rf`, `FileUtils.rm_f`, " \
+ "or `{FileUtils,Pathname}.rmtree`."
 
  def_node_matcher :fileutils_rm_r_f?, <<~PATTERN
  (send (const {nil? cbase} :FileUtils) {:rm_rf :rm_f :rmtree} ...)
  PATTERN
 
+ def_node_matcher :pathname_rmtree?, <<~PATTERN
+ (send (const {nil? cbase} :Pathname) :rmtree ...)
+ PATTERN
+
  def on_send(node)
- return unless fileutils_rm_r_f?(node)
+ return unless fileutils_rm_r_f?(node) || pathname_rmtree?(node)
 
  add_offense(node) do |corrector|
  new_method = if node.method?(:rm_rf) || node.method?(:rmtree)
  "rm_r"
  else
  "rm"
  end
+
  corrector.replace(node.loc.expression, "FileUtils.#{new_method}(#{node.arguments.first.source})")
  end
  end

Library/Homebrew/test/rubocops/no_fileutils_rmrf_spec.rb

@@ -60,5 +60,24 @@
  FileUtils.rm_r("path/to/directory")
  RUBY
  end
+
+ describe "Pathname.rmtree" do
+ it "registers an offense when using Pathname.rmtree" do
+ expect_offense(<<~RUBY)
+ Pathname.rmtree("path/to/directory")
+ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Homebrew/NoFileutilsRmrf: #{RuboCop::Cop::Homebrew::NoFileutilsRmrf::MSG}
+ RUBY
+ end
+
+ it "autocorrects" do
+ corrected = autocorrect_source(<<~RUBY)
+ Pathname.rmtree("path/to/directory")
+ RUBY
+
+ expect(corrected).to eq(<<~RUBY)
+ FileUtils.rm_r("path/to/directory")
+ RUBY
+ end
+ end
  end
 end