Recognize \0 as an escape sequence

Closes microsoft/monaco-editor/issues/3439

src/basic-languages/cpp/cpp.ts

@@ -272,7 +272,7 @@ export const language = <languages.IMonarchLanguage>{
 
 	// we include these common regular expressions
 	symbols: /[=><!~?:&|+\-*\/\^%]+/,
-	escapes: /\\(?:[abfnrtv\\"']|x[0-9A-Fa-f]{1,4}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8})/,
+	escapes: /\\(?:[0abfnrtv\\"']|x[0-9A-Fa-f]{1,4}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8})/,
 	integersuffix: /([uU](ll|LL|l|L)|(ll|LL|l|L)?[uU]?)/,
 	floatsuffix: /[fFlL]?/,
 	encoding: /u|u8|U|L/,