doc: contribute.html | "Making a Change" should be replaced with "Before Contributing code"

[mbj36]

Please answer these questions before submitting your issue. Thanks!

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

1.10.1

Does this issue reproduce with the latest release?

yes

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

GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/mbj36/Library/Caches/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/mbj36/go"
GORACE=""
GOROOT="/usr/local/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
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 -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/5n/xxkj67y13t3fmbpdzhvwr92r0000gn/T/go-build269385616=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

https://tip.golang.org/doc/contribute.html#making_a_change this doesn;t jump to anywhere

If possible, provide a recipe for reproducing the error.
A complete runnable program is good.
A link on play.golang.org is best.

What did you expect to see?

It should go to https://tip.golang.org/doc/contribute.html#before_contributing

What did you see instead?

Nothing happens

[gopherbot]

Change https://golang.org/cl/125975 mentions this issue: doc: fix link in contribute.html

[gopherbot]

Change https://golang.org/cl/126935 mentions this issue: doc: fix link in contribute.html