Hide "CSS Critical Path" mentioned in documentation pages as it is not port of stable Magento version yet (nor 2.2 or 2.3)

[vasilii-b]

Purpose of this pull request

Hide "CSS Critical Path" page from documentation and mentions in other pages as this feature is only present in 2.3-develop branch:

Magento 2.2

Magento 2.3

• Remove "CSS Critical Path" page. from the v2.2 documentation
  This feature is not available in 2.2 version.
• Move "CSS Critical Path" page to v2.3 of documentation

Note: Original PR #4726 was merged to master when he had to be merged to develop, most probably. Also, it was not pointing to the Magento source code.

This is confusing for Front-End developers, as they are provided a feature that can't be used actually.

Affected DevDocs pages

• https://devdocs.magento.com/guides/v2.2/frontend-dev-guide/css-topics/css-critical-path.html
• https://devdocs.magento.com/guides/v2.3/frontend-dev-guide/css-topics/css-critical-path.html
• https://devdocs.magento.com/guides/v2.2/frontend-dev-guide/css-topics/css-overview.html
• https://devdocs.magento.com/guides/v2.3/frontend-dev-guide/css-topics/css-overview.html

Links to Magento source code

• https://github.com/magento/magento2/blob/2.2/app/code/Magento/Theme/view/frontend/layout/default_head_blocks.xml
• https://github.com/magento/magento2/blob/2.3/app/code/Magento/Theme/view/frontend/layout/default_head_blocks.xml
• https://github.com/magento/magento2/blob/2.3-develop/app/code/Magento/Theme/view/frontend/layout/default_head_blocks.xml

[devops-devdocs]

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

[rogyar]

Do we still need the following file guides/v2.3/frontend-dev-guide/css-topics/css-critical-path.md ?
I believe it should be removed as well. Even if we don't have links to this topic, it might be still indexable by search crawlers.

[rogyar]

I can confirm that the mentioned functionality is not present in the latest release yet. We do have the same documentation in the develop branch so it won't be missing.
However, I'm not sure how we should handle such cases when we need to re-add some info from develop branch after a new release once it has been removed from master branch @keharper
Thank you

[vasilii-b]

Hi @rogyar ,
I wasn't sure how we should proceed here:

Do we still need the following file guides/v2.3/frontend-dev-guide/css-topics/css-critical-path.md ?
I believe it should be removed as well. Even if we don't have links to this topic, it might be still indexable by search crawlers.

But after it's confirmed that changes are present in the develop branch we can remove the file at all. Totally agree here.

Thank you!

[bdenham]

running tests

[bdenham]

Looks good guys! Thank you for correcting this.

[keharper]

@rogyar @vasilii-b I'm just now seeing this PR. Since the PR affects the Frontend Development Guide, I probably ignored the thread.

Since the contributor of #4726 is an Adobe employee, I think the functionality being documented will be in the 2.3.4 release. I think the content that was removed in this PR should be added back, but in the Q4-integration branch.

[hostep]

@keharper: the functionality is definitely part of Magento 2.3.3

So this content should be restored in master in a few days when 2.3.3 is opened to the public.

[keharper]

Thanks for confirming, @hostep.

If at all possible, the info should be restored to the develop branch before it gets merged to master for 2.3.3 on Tuesday morning (Austin time). That's a very short turnaround time, and might not be realistic.

I became aware of this PR because @jfrontain asked me about the deleted file, which was to be referenced in the release notes. It'd be nice to include the reference without having to update the release notes later on.

[keharper]

I created the PR myself. #5586