Typo in CLI usage string for diff subcommand

[mickeyreiss]

Describe the bug

I believe there is a typo here:

https://github.com/google/wire/blob/0ac845078ca01a1755571c53d7a8e7995b96e40d/cmd/wire/main.go#L182-L193

To Reproduce

Run wire diff -h.

Expected behavior

Similar to the **diff** command should probably read Similar to the **check** command

Version

0.5.0

Additional context

Add any other context about the problem here.