Remove unused Csi methods

It's hard to keep Csi.color_enabled and
SuperDiff::Configuration.color_enabled in sync. But Csi.color_enabled is
only serving Csi.colorize, which in turn only exists for
Csi.inspect_colors_in, which is apparently unused elsewhere in this
project.

Since Csi is a library private to this project, we can remove them.

lib/super_diff.rb

@@ -36,7 +36,6 @@ def self.const_missing(missing_const_name)
 
   def self.configure
     yield configuration
-    configuration.updated
   end
 
   def self.configuration

lib/super_diff/core/configuration.rb

@@ -71,12 +71,6 @@ def merge!(configuration_or_options)
           end
 
         options.each { |key, value| instance_variable_set("@#{key}", value) }
-
-        updated
-      end
-
-      def updated
-        SuperDiff::Csi.color_enabled = color_enabled?
       end
 
       def add_extra_diff_formatter_classes(*classes)

lib/super_diff/core/helpers.rb

@@ -6,7 +6,7 @@ module Helpers
       # TODO: Simplify this
       def style(*args, color_enabled: true, **opts, &block)
         klass =
-          if color_enabled && Csi.color_enabled?
+          if color_enabled && SuperDiff.configuration.color_enabled?
             Csi::ColorizedDocument
           else
             Csi::UncolorizedDocument

lib/super_diff/csi.rb

@@ -12,48 +12,16 @@ module Csi
     autoload :TwentyFourBitColor, "super_diff/csi/twenty_four_bit_color"
     autoload :UncolorizedDocument, "super_diff/csi/uncolorized_document"
 
-    class << self
-      attr_writer :color_enabled
-    end
-
     def self.reset_sequence
       ResetSequence.new
     end
 
-    def self.color_enabled?
-      @color_enabled
-    end
-
-    def self.colorize(*args, **opts, &block)
-      if color_enabled?
-        ColorizedDocument.new(*args, **opts, &block)
-      else
-        UncolorizedDocument.new(*args, **opts, &block)
-      end
-    end
-
     def self.decolorize(text)
       text.gsub(/\e\[\d+(?:;\d+)*m(.+?)\e\[0m/, '\1')
     end
 
     def self.already_colorized?(text)
       text.match?(/\e\[\d+m/)
     end
-
-    def self.inspect_colors_in(text)
-      [FourBitColor, EightBitColor, TwentyFourBitColor].reduce(
-        text
-      ) do |str, klass|
-        klass.sub_colorized_areas_in(str) do |area, color|
-          color_block = colorize("◼︎", color.to_foreground)
-
-          layer_indicator = (color.foreground? ? "(fg)" : "(bg)")
-
-          "#{color_block} #{layer_indicator} ❮#{area}❯"
-        end
-      end
-    end
-
-    self.color_enabled = false
   end
 end