Issue of multiple filters

Hi, devs,

I'm rewriting some log4j1 properties to log4j2. One issue I encounter now is multiple filters:

```
appender.console.filter.1.type = Filters
appender.console.filter.1.a.type = ThresholdFilter
appender.console.filter.1.a.level = warn

appender.console.filter.1.b.type = MarkerFilter
appender.console.filter.1.b.marker = Thrift error occurred during processing of message
appender.console.filter.1.b.onMatch = deny
appender.console.filter.1.b.onMismatch = neutral
```


I follow some examples I can find to write it as above. But I got an error:

```
2021-12-17 14:22:26,163 pool-1-thread-1 ERROR Filters contains invalid attributes "onMatch", "onMismatch"
2021-12-17 14:22:26,176 pool-1-thread-1 ERROR Filters contains invalid attributes "onMatch", “onMismatch"
```

Seems onMatch/onMismatch is (wrongly) considered as attributes of Filters ?
Am I writing multiple filters wrong? Any suggestion? Thanks.

Liang-Chi