(PUP-11993) Move Style/PreferredHashMethods to .rubocop.yml

This commit moves Style/PreferredHashMethods from .rubocop_todo.yml
to .rubocop.yml to indefinitely disable the cop. This is because enabling
this cop causes 11 failures in rb_tree_map_spec.rb that relate to core
functions in trees, like deleting a node and returning nil when a key
can't be found.

Author: AriaXLi

.rubocop.yml

@@ -51,6 +51,12 @@ Style/RedundantSelfAssignment:
   Exclude:
     - 'lib/puppet/context.rb'
 
+# Enabling this cop causes failures in rb_tree_map_spec relating to important
+# function slike being unable to delete nodes and returning nil when the key
+# cannot be found
+Style/PreferredHashMethods:
+  Enabled: false
+
 # Explicitly enables this cop new in 1.7
 Layout/SpaceBeforeBrackets:
   Enabled: true

.rubocop_todo.yml

@@ -646,12 +646,6 @@ Style/NumericPredicate:
 Style/OptionalBooleanParameter:
   Enabled: false
 
-# This cop supports unsafe auto-correction (--auto-correct-all).
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: short, verbose
-Style/PreferredHashMethods:
-  Enabled: false
-
 # This cop supports safe auto-correction (--auto-correct).
 # Configuration parameters: EnforcedStyle.
 # SupportedStyles: implicit, explicit