packages feed

pandoc-3.10: test/command/11384.md

```
% pandoc -t markdown -f native
[ Para [ Math DisplayMath "\ne = mc^2\n" ] ]
^D
$$
e = mc^2
$$
```

But we need to collapse spaces around inline math:

```
% pandoc -t markdown -f native
[ Para [ Math InlineMath "\ne=mc\n" ]]
^D
$e=mc$
```