`compound-attribute-name` lint doesn't detect bad attribute names in formations

How about we prohibit compound attribute names, as suggested here: https://www.yegor256.com/2015/01/12/compound-name-is-code-smell.html

This lint should not complain about formations, but only about attributes inside them. This is valid:

```
[] > foo-bar # good name
```

This is not valid:

```
[] > x
  42 > foo-bar  # bad name
```