Revert "crypto/sha256: add WriteString and WriteByte method"
This reverts CL 481478
Reason for revert: can cause cgo errors when using boringcrypto.
See #59954.
For #38776
For #59954
Change-Id: Ic520f9fede152d22ab69996ad84c44f3e0d783bc
Reviewed-on: https://go-review.googlesource.com/c/go/+/492356 Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com> Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>