<!--- Verify first that your issue is not already reported on GitHub -->
<!--- Also test if the latest release and devel branch are affected too -->
<!--- Complete *all* sections as described, this form is processed automatically -->

##### SUMMARY
<!--- Explain the problem briefly below -->
When encrypting a single variable from sdtin the resulting output appears right after the value.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
`ansible/lib/ansible/cli/vault.py`

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
ansible --version
ansible 2.9.1
  config file = /Users/alexandrechouinard/.ansible.cfg
  configured module search path = ['/Users/alexandrechouinard/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /Users/alexandrechouinard/workspace/repos/ops2.0/provisioning-prometheus-vm/venv/lib/python3.7/site-packages/ansible
  executable location = /Users/alexandrechouinard/workspace/repos/ops2.0/provisioning-prometheus-vm/venv/bin/ansible
  python version = 3.7.4 (default, Sep  7 2019, 18:27:02) [Clang 10.0.1 (clang-1001.0.46.4)]
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below
ansible-config dump --only-changed

DEFAULT_REMOTE_USER(env: ANSIBLE_REMOTE_USER) = alexc
```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
Mac OSX

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->
1. Encrypt a string using STDIN
1. Input vault password 2 times
1. Type variable value
1. Input ctrl+d two times

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
```
ansible-vault encrypt_string --stdin-name 'variable'
New Vault password: 
Confirm New Vault password: 
Reading plaintext input from stdin. (ctrl-d to end input)
value
variable: !vault |
          $ANSIBLE_VAULT;1.1;AES256
          63393237383235396431646465663363663433366232623736633136313039626264663832333731
          6136373531393136656135343135393964393439633038610a313130336635366362316264343662
          32343834656337643338393430636533366131326166323934623834646335626639393835393762
          3530306336356336660a306366333839376364666561613736306261393966613035623763366564
          3636
Encryption successful
```

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->

<!--- Paste verbatim command output between quotes -->
```
ansible-vault encrypt_string --stdin-name 'variable'
New Vault password: 
Confirm New Vault password: 
Reading plaintext input from stdin. (ctrl-d to end input)
valuevariable: !vault |
          $ANSIBLE_VAULT;1.1;AES256
          63393237383235396431646465663363663433366232623736633136313039626264663832333731
          6136373531393136656135343135393964393439633038610a313130336635366362316264343662
          32343834656337643338393430636533366131326166323934623834646335626639393835393762
          3530306336356336660a306366333839376364666561613736306261393966613035623763366564
          3636
Encryption successful
```

indent = indent or 10
        block_format_var_name = ""
        if name:
            block_format_var_name = "%s: " % name
        block_format_header = "%s!vault |" % block_format_var_name
        lines = []
        vault_ciphertext = to_text(b_ciphertext)
        lines.append(block_format_header)
        for line in vault_ciphertext.splitlines():
            lines.append('%s%s' % (' ' * indent, line))
        yaml_ciphertext = '\n'.join(lines)
        return yaml_ciphertext
    def execute_encrypt_string(self):
        ''' encrypt the supplied string using the provided vault secret '''
        b_plaintext = None
        
        b_plaintext_list = []
        
        
        args = [x for x in context.CLIARGS['args'] if x != '-']
        
        if context.CLIARGS['encrypt_string_prompt']:
            msg = "String to encrypt: "
            name = None
            name_prompt_response = display.prompt('Variable name (enter for no name): ')