Trailing right bracket is stripped off values

Preflight Checklist

• I have searched the issue tracker for an issue that matches the one I want to file, without success.
• I am not looking for support or already pursued the available support channels without success.
• I have checked the troubleshooting guide for my problem, without success.

Viper Version

1.15.0

Go Version

1.18

Config Source

Flags

Format

Other (specify below)

Repl.it link

No response

Code reproducing the issue

package main

import (
	"fmt"
	"os"

	"github.com/spf13/pflag"
	"github.com/spf13/viper"
)

func main() {
	v := viper.New()
	flags := pflag.NewFlagSet("viper-example", pflag.ExitOnError)
	flags.StringToString("bug", map[string]string{}, "Demo of bug.")
	v.BindPFlags(flags)
	if err := flags.Parse(os.Args[1:]); err != nil {
		panic(err)
	}
	m := v.GetStringMapString("bug")
	fmt.Printf("bug[foo]: %v\n", m["foo"])
}

Expected Behavior

When run with --bug "foo=bar]": Expected Output bug[foo]: bar]

Actual Behavior

When run with --bug "foo=bar]": Actual Output bug[foo]: bar

Steps To Reproduce

No response

Additional Information

No response