[10.X] Document update/save/delete or fail methods

[peterfox]

Based on the following PRs that don't appear to be documented:

laravel/framework#38784
laravel/framework#11202
laravel/framework#38592

[taylorotwell]

I think I would rather just direct people towards using transactions explicitly.

[peterfox]

@taylorotwell totally understand. I'm curious should the methods not be deprecated in a future release if they're not documented? Seems odd to keep them in but also no encourage their use.

[alexanderkroneis]

@taylorotwell totally understand. I'm curious should the methods not be deprecated in a future release if they're not documented? Seems odd to keep them in but also no encourage their use.

Laravel has a lot of functionality which is not documented (yet). Not all of them are deprecated, it's mostly just another way of solving a problem.