remove the rouge copypasta and add notes to refactor

lib/rouge/lexers/math.rb

 module Rouge
   module Lexers
-    class Math < Lexer
+    class Math < PlainText
       title "A passthrough lexer used for LaTeX input"
-      desc "A boring lexer that doesn't highlight anything"
-
+      desc "PLEASE REFACTOR - this should be handled by SyntaxHighlightFilter"
       tag 'math'
-      mimetypes 'text/plain'
-
-      default_options token: 'Text'
-
-      def token
-        @token ||= Token[option :token]
-      end
-
-      def stream_tokens(string, &b)
-        yield self.token, string
-      end
     end
   end
 end

lib/rouge/lexers/plantuml.rb

 module Rouge
   module Lexers
-    class Plantuml < Lexer
+    class Plantuml < PlainText
       title "A passthrough lexer used for PlantUML input"
-      desc "A boring lexer that doesn't highlight anything"
-
+      desc "PLEASE REFACTOR - this should be handled by SyntaxHighlightFilter"
       tag 'plantuml'
-      mimetypes 'text/plain'
-
-      default_options token: 'Text'
-
-      def token
-        @token ||= Token[option :token]
-      end
-
-      def stream_tokens(string, &b)
-        yield self.token, string
-      end
     end
   end
 end