x/text/currency: add support for integer

[YunxiangHuang]

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

$ go version
go version go1.12.6 darwin/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
GOARCH="amd64"

GOBIN=""

GOCACHE="/Users/yunxiang.huang/Library/Caches/go-build"

GOEXE=""

GOFLAGS=""

GOHOSTARCH="amd64"

GOHOSTOS="darwin"

GOOS="darwin"

GOPATH="/Users/yunxiang.huang/Work/go"

GOPROXY=""

GORACE=""

GOROOT="/usr/local/Cellar/go/1.12.6/libexec"

GOTMPDIR=""

GOTOOLDIR="/usr/local/Cellar/go/1.12.6/libexec/pkg/tool/darwin_amd64"

GCCGO="gccgo"

CC="clang"

CXX="clang++"

CGO_ENABLED="1"

GOMOD=""

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/nz/kfm5t8n50dq8gz79ln3jfchc0000gn/T/go-build553255337=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

package main

import (
	"fmt"

	"golang.org/x/text/currency"
)

func main() {
	cur := currency.MustParseISO("CNY")
	fmt.Println(currency.NarrowSymbol(cur.Amount(0)))
	fmt.Println(currency.Symbol(cur.Amount(0)))
}

What did you expect to see?

￥0.00
CN¥ 0.00

What did you see instead?

¥ %!f(int=00)
CN¥ %!f(int=00)

[andybons]

@mpvl

[rhnvrm]

@andybons @mpvl @YunxiangHuang - I'd be happy to work on this issue

[AlexanderYastrebov]

Should be fixed by golang/text#27

[elliotwutingfeng]

This appears to be fixed as of Go 1.19