Transform methods `look_to` and `look_at` are confusing

## How can Bevy's documentation be improved?

What's the difference between "looking at smth" and "looking to smth"?

Difficult to tell… Yet Transform has two distinct methods on Transform called look_to and look_at. One considers the argument a relative position to look toward (a direction), the other considers the argument as an absolute position to look toward (a position).

Code review during #6692 said that `look_to` could lead to confusion.

### Solution

I thought about this a bit, and there isn't a perfect solution.

However, I suggest replacing `look_to` by `look_in`. Why? Because it's grammatically incorrect to say "look in enemy", but it's grammatically correct to say "look in direction".

Start with the Transform::look_to and Transform::look_at APIs and their documentation to understand how direction and position arguments are described. Evaluate whether the proposed look_in name resolves the confusion, and consider the affected API references; done means the naming and documentation change are agreed and the distinction is clear.

Written by the indexing model from the issue text.