Fix improper syntax highlighting for in expressions

src/theme/pluto.js

@@ -1,6 +1,6 @@
 Prism.languages.pluto = {
 	'comment': /^#!.+|--(?:\[(=*)\[[\s\S]*?\]\1\]|.*)/m,
-	'function': /(?!\d)\w+(?=\s*(?:[({"]))/,
+	'function': /\b(?!in\s)(?!\d)\w+(?=\s*(?:[({"]))/,
 	'string': {
 		pattern: /(["'])(?:(?!\1)[^\\\r\n]|\\z(?:\r\n|\s)|\\(?:\r\n|[^z]))*\1|\[(=*)\[[\s\S]*?\]\2\]/,
 		greedy: true
@@ -10,7 +10,7 @@ Prism.languages.pluto = {
 	'keyword': /\$|\b(?:and|as|class|pluto_class|enum|begin|break|do|else|elseif|end|for|function|goto|if|in|local|new|not|or|repeat|return|static|then|until|while|continue|switch|case|default|pluto_switch|pluto_continue|extends|export|pluto_export|pluto_use|public)\b/,
 	'variable': /\b(?:self|parent|pluto_parent)\b/,
 	'operator': [
-		/[-+*%^&|#]|\/\/?|<[<=]?|>[>=]?|[=~]=?|\:=|\?|\:|\?\.|instanceof/,
+		/[-+*%^&|#]|\/\/?|<[<=]?|>[>=]?|[=~]=?|\:=|\?|\:|\?\.|instanceof|in/,
 		{
 			pattern: /(^|[^.])\.\.(?!\.)/,
 			lookbehind: true