remove filter for Note class
remove filter for Note class


The Note class actually represents *footnotes*:
```
echo "hello^[footnote ...] world" | pandoc -t native
[Para [Str "hello",Note [Para [Str "footnote",Space,Str "..."]],Space,Str "world"]]
```

There is no connection to notes as in
```
echo "hello [notes ...]{.notes} world" | pandoc -t native
[Para [Str "hello",Space,Span ("",["notes"],[]) [Str "notes",Space,Str "..."],Space,Str "world"]]
```


Should really be documented somewhere!

cagix/pandoc-lecture