I had mixed feelings about this rule, since I like spaces where
possible.
However, I changed my mind when I realized writing `->(thing) { }` was
similar to defining a method, and we don't have a space before the
parenthesis when defining a method.
Not doing so has a few gotchas when working with relations, particularly
with records which are not stored in the database.
I'm excluding the related content file because it's got a very peculiar
relationship with itself: the `has_one :opposite_related_content` has no
inverse; the relation itself is its inverse. It's a false positive since
the inverse condition is true:
```
content.opposite_related_content.opposite_related_content.object_id ==
content.object_id
```
