Allow checking that excluded errors are always ignored

[krobelus]

We have code like

buffer := bytes.Buffer{}
_, _ = buffer.WriteString("")

We always want to ignore these errors, so I want to add some -exclude or -ignore rules and use

buffer := bytes.Buffer{}
buffer.WriteString("")

However, to keep to code consistent we also need to guard against accidentally using the deprecated _, _ = buffer.WriteString("") in future.

Would it be reasonable to be able to say "make sure that errors from bytes.Buffer.Write* are never used"?

I'm thinking of adding a global flag that enables this check for all excluded errors. Are there errors that need only be checked sometimes? :thinking: I can't think of any.