TOML keys are not read if they contain a dot

[greg-szabo]

Expected behavior (what you expected to happen):
Unquoted TOML entries with a dot should be read properly:

[section1]
la.la="one"
[section2]
"la.la"="two"

section1.la.la should read one.

Actual behavior (what actually happened):
Only section2.la.la will be available, not section1.la.la contrary to the TOML definition.

Repl.it link:

https://replit.com/@gregszabo/TOMLExample3

Code reproducing the issue:

package main

import (
	"bytes"
	"fmt"
	"github.com/spf13/viper"
)

func main() {

var tomlExample1 = []byte(`
[something]
la="one"
`)

var tomlExample2 = []byte(`
[something]
la.la="two"
`)

var tomlExample3 = []byte(`
[something]
"la.la"="three"
`)


	viper.SetConfigType("toml")

	viper.ReadConfig(bytes.NewBuffer(tomlExample1))
	fmt.Printf("%v\n",viper.AllKeys())

	viper.ReadConfig(bytes.NewBuffer(tomlExample2))
	fmt.Printf("%v\n",viper.AllKeys())

	viper.ReadConfig(bytes.NewBuffer(tomlExample3))
	fmt.Printf("%v\n",viper.AllKeys())

  // From https://toml.io/en/v1.0.0#keys
  //   Dotted keys are a sequence of bare or quoted keys joined with a dot. This allows for grouping similar properties together
  // Output:
  //   [something.la]
  //   []
  //   [something.la.la]
  // Expected output:
  //   [something.la]
  //   [something.la.la]
  //   [something.la.la]
}

Environment:

• Viper version: v1.7.1
• Config source: file
• File format: TOML

Anything else we should know?:

[github-actions]

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