Parser.parseMixin

Parses a MixinDecl or MixinStmt. $(BNF /MixinDecl := (MixinExpr | MixinTemplate | MixinTemplateId) ";" /MixinExpr := mixin "(" AssignExpr ")" /MixinTemplate := mixin TemplateDecl # D2 /MixinTemplateId := mixin TemplateIdentifier / ("!" "(" TemplateArguments ")")? MixinIdentifier?)