git apply --check should give some indication that a patch applies cleanly

Hi folks,

The main purpose of `git apply --check` is to see if a patch can apply.

It's not intuitive to a user, just from the command name, that "no output" means your patch can apply cleanly.

Furthermore, `git apply --check --verbose` only says that it is checking the patch, ending with "..." which usually means "more info to come"... But it doesn't print anything else. An example command and output:

``` $ git apply --check --verbose [my-patch.patch] Checking patch [path/to/file.ext]... ```

I'd like if there were some way for the command to confirm outright that the patch applies, to save users the confusion.

Thanks.