<!--- 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
```

raise AnsibleOptionsError("A vault password is required to use Ansible's Vault")
        if action in ['encrypt', 'encrypt_string', 'create']:
            encrypt_vault_id = None
            
            if action not in ['edit']:
                encrypt_vault_id = context.CLIARGS['encrypt_vault_id'] or C.DEFAULT_VAULT_ENCRYPT_IDENTITY
            vault_secrets = None
            vault_secrets = \
                self.setup_vault_secrets(loader,
                                         vault_ids=vault_ids,
                                         vault_password_files=list(context.CLIARGS['vault_password_files']),
                                         ask_vault_pass=context.CLIARGS['ask_vault_pass'],
                                         create_new_password=True)
            if len(vault_secrets) > 1 and not encrypt_vault_id:
                raise AnsibleOptionsError("The vault-ids %s are available to encrypt. Specify the vault-id to encrypt with --encrypt-vault-id" %
                                          ','.join([x[0] for x in vault_secrets]))
            if not vault_secrets:
                raise AnsibleOptionsError("A vault password is required to use Ansible's Vault")
            encrypt_secret = match_encrypt_secret(vault_secrets,
                                                  encrypt_vault_id=encrypt_vault_id)
            
            
            self.encrypt_vault_id = encrypt_secret[0]
            self.encrypt_secret = encrypt_secret[1]
        if action in ['rekey']:
            encrypt_vault_id = context.CLIARGS['encrypt_vault_id'] or C.DEFAULT_VAULT_ENCRYPT_IDENTITY