Described missed prompt widget options and added code samples of prompt widget initialization

[serhiyzhovnir]

Purpose of this pull request

This pull request (PR) describes missed options of the prompt widget and also it adds the code samples of the prompt widget initialization.
The PR is an adjusted copy of #4736 PR.
I've created it on purpose to not to increase repo size too much.

Affected DevDocs pages

• https://devdocs.magento.com/guides/v2.3/javascript-dev-guide/widgets/widget_prompt.html
• https://devdocs.magento.com/guides/v2.2/javascript-dev-guide/widgets/widget_prompt.html

Links to Magento source code

• https://github.com/magento/magento2/blob/2.3/app/code/Magento/Ui/view/base/web/templates/modal/modal-prompt-content.html
• https://github.com/magento/magento2/blob/2.2/app/code/Magento/Ui/view/base/web/templates/modal/modal-prompt-content.html
• https://github.com/magento/magento2/blob/2.2/app/code/Magento/Ui/view/base/web/js/modal/prompt.js
• https://github.com/magento/magento2/blob/2.3/app/code/Magento/Ui/view/base/web/js/modal/prompt.js
• https://github.com/magento/magento2/blob/2.2/app/code/Magento/Catalog/view/adminhtml/templates/catalog/product/attribute/set/main.phtml#L283
• https://github.com/magento/magento2/blob/2.3/app/code/Magento/Catalog/view/adminhtml/templates/catalog/product/attribute/set/main.phtml#L282

whatsnew
Completed the reference list and added a 'Code sample' section to the Prompt Widget topic.

[devops-devdocs]

An admin must run tests on this PR before it can be merged.

[rogyar]

Please, do not capitalize the "Admin" word. In this case, we don't describe a product name or a personal name. Thank you.
https://github.com/magento/devdocs/pull/4782/files#diff-4671b33861390321846f924cf04f205eR15

[rogyar]

Please, do not capitalize the "Admin" word. In this case, we don't describe a product name or a personal name. Thank you.
https://github.com/magento/devdocs/pull/4782/files#diff-4671b33861390321846f924cf04f205eR15

Nevermind. I've just noticed that this change is from the previous version. Thank you

[dobooth]

running tests

[ghost]

Hi @serhiyzhovnir, thank you for your contribution!
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[meker12]

@dobooth Please add the whatsnew info to the PR description. Thx.