x/net/context: deprecate package or symbols in package

[frioux]

What version of Go are you using (go version)?

$ go version
go version go1.17.1 linux/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/frew/.cache/go-build"
GOENV="/home/frew/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS="-mod=readonly"
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/frew/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/frew/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org"
GOROOT="/home/frew/go/installations/go1.17.1"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/frew/go/installations/go1.17.1/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.17.1"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/frew/code/zr0/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/run/shm/go-build2449590503=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Accidentally used golang.org/x/net/context

What did you expect to see?

A deprecation warning caught by our linter. Basically I think we should mark the package (or symbols in the package) deprecated so that linters would notice and automatically suggest people switch to context.

What did you see instead?

Nothing.

[cagedmantis]

/cc @neild @ianlancetaylor

[neild]

The context package has been in the standard library for a long time. Deprecating x/net/context seems reasonable.