compare unwrapped errors using DeepEqual

[tareksha]

Currently when the actual error is check by MatchError, it matches in two cases:

1. The built-in errors.Is(..) returns true
2. the actual error deep-equals the matcher error

this change expands the second case and performs DeepEqual on each error in the chain of unwrapping. This allows matching complex errors that are wrapped, for example:

err := fmt.Errorf("internal error: %w", MyKeyError{Key: "alice})

Expect(err).To(MatchError(MyKeyError{Key: "alice}))

[onsi]

Looks good to me - thanks!

Would you be up for updating the docs here:

https://onsi.github.io/gomega/#matcherrorexpected-interface

(it's the index.md file in the docs directory)

[tareksha]

@onsi done

[onsi]

perfect, thanks!

[tareksha]

@onsi thanks for accepting the change. when is this expected to be released?

[onsi]

hey - I'll cut a release once #619 gets merged in.

[onsi]

this just shipped in 1.25.0