note about ref patterns in pointer guide

[steveklabnik]

Fixes #13602

[thehydroimpulse]

This initially came across as you were going to show an invalid case before the correct one, so it's kinda confusing as the user has no idea which error you're talking about.

Thoughts?

[MatejLach]

Maybe a simple edit along the lines of "When you're trying to match something that's stored in a pointer, there may be a situation where using y directly isn't the best option available. Here's some code:" will do?

[thehydroimpulse]

I think it's the "here's some code" that isn't doing it. Perhaps something like, `Let's see how we can approach it better" or something like that so they know they're looking at the correct version, not the faulty one.

I like the rest of @MatejLach's suggestion, though.

[steveklabnik]

Thanks everyone! Took those suggestions into account. What do you think now?

[thehydroimpulse]

Much better :)

[MatejLach]

@thehydroimpulse +1