Merge pull request cockroachdb#67 from knz/20210413-proto

Update to gogoproto 1.3.

extgrpc: add support for automatic en/decoding of gRPC Status

This patch adds support for automatic en/decoding of gRPC `Status`
errors, enabled by importing the `extgrpc` package. It supports statuses
generated both by the standard `google.golang.org/grpc/status` and the
gogoproto-based `github.com/gogo/status` packages.

Encoded statuses are always represented as `gogo/status`-based `Status`
Protobufs, since the `EncodedError` type is a gogoproto type using an
`Any` field for structured errors, and only gogoproto types can be
placed here since standard Protobufs are not registered in the gogoproto
type registry. We lock the `gogo/googleapis` package to 1.2.0 to
use gogoproto 1.2-compatible Protobufs required by CRDB, these have been
verified to not be vulnerable to the "skippy pb" bug.

Note that to preserve error details, gogo-based `Status` objects with
gogo-based details must be used, otherwise details may not be preserved.
This is for similar reasons as outlined above, and is a limitation in
the gRPC package -- see code comments for further details. A CRDB linter
rule forbidding use of `Status.WithDetails()` was submitted in
cockroachdb/cockroach#61617.

Merge pull request cockroachdb#59 from knz/20201212-errors

markers: delegate to an Is() method if present

Merge pull request cockroachdb#55 from knz/20201106-redact-fmt

Bump redact to get the fix to the string builder fmt bug

README: fix typo

Check that nil parameters don't get redacted in the -f() variants.

Bump the redact dep to get a minor API benefit.

Make errors.Formattable more useful, fix a redact bug

This patch ensures that the result value from errors.Formattable
also implements error, so that detailed error output is properly
produced if formatted via %+v.

It also bumps the redact dependency to fix a bug.

Fix a silly bug

Make `WithSafeDetails` more useful

Prior to this patch, `WithSafeDetails` was capturing safe strings but
they were not shown in the output of `%+v`. This choice was made at
the time where `WithSafeDetails` was the only way for `errors.New` to
capture safe strings for reporting. At that time, displaying the safe
strings in the `%+v` output would *duplicate* error messages: once
from the `Error()` output, and one from the safe details.

Since v1.7, `errors.New` and related functions do not use
`WithSafeDetails` any more. The risk for data duplication is thus
removed. So this patch evolves the wrapper produced by
`WithSafeDetails` to also report its safe strings during `%+v`
renderings.

Additionally, the logic for `WithSafeDetails` previously duplicated
information from the arguments: the text would be rendered once
in full in the first detail string, then each argument would be
detailed further (with type information and all) in additional
strings. For example:

```
WithSafeDetails("hello ", redact.Safe("world"))

  (1) 2 safe details enclosed
    | hello world
    | -- arg 1 (string): world
```

(See how "world" is duplicated)

In practice, this amount of detailing has not proven useful, and
it is in fact detrimental to the readability of error strings.

So this patch removes it. The new output for the example above is:

```
  (1) hello world
```