Added async and await as C# keywords.

modules/mono/csharp_script.cpp

@@ -176,7 +176,7 @@ void CSharpLanguage::get_reserved_words(List<String> *p_words) const {
 		"fixed",
 		"float",
 		"for",
-		"forech",
+		"foreach",
 		"goto",
 		"if",
 		"implicit",
@@ -222,14 +222,17 @@ void CSharpLanguage::get_reserved_words(List<String> *p_words) const {
 		"ushort",
 		"using",
 		"virtual",
-		"volatile",
 		"void",
+		"volatile",
 		"while",
 
 		// Contextual keywords. Not reserved words, but I guess we should include
 		// them because this seems to be used only for syntax highlighting.
 		"add",
+		"alias",
 		"ascending",
+		"async",
+		"await",
 		"by",
 		"descending",
 		"dynamic",
@@ -238,10 +241,10 @@ void CSharpLanguage::get_reserved_words(List<String> *p_words) const {
 		"get",
 		"global",
 		"group",
-		"in",
 		"into",
 		"join",
 		"let",
+		"nameof",
 		"on",
 		"orderby",
 		"partial",
@@ -250,6 +253,7 @@ void CSharpLanguage::get_reserved_words(List<String> *p_words) const {
 		"set",
 		"value",
 		"var",
+		"when",
 		"where",
 		"yield",
 		0