Rule one-declaration-per-line
will enforce that new declarations must begin on new lines.
When enabled, the following are allowed:
.foo {
content: 'baz';
content: 'qux';
}
When enabled, the following are disallowed:
.foo {content: 'baz', content: 'qux'};
.foo {
content: 'baz'; content: 'qux';
}