Removed useless rule

lib/ace/mode/praat_highlight_rules.js

@@ -135,10 +135,6 @@ var PraatHighlightRules = function() {
                 token : ["text", "support.function", "text"],
                 regex : /(\s*)(do\$?)(\s*:\s*|\s*\(\s*)/
             }, {
-            // Is this rule necessary?
-            //     token : ["text", "keyword"],
-            //     regex : /(^\s*)(demo\b)/
-            // }, {
             // Object types
                 token : "entity.name.type",
                 regex : "(" + objectTypes + ")"