Fix default theme headers to add `Requires at least` and `Requires PHP` headers

[afragen]

Per the discussion in #48515 this ticket is to have the headers for all the default themes have their respective Requires at least and Requires PHP headers in the style.css files.

Also, please do not include the WordPress in the version number for the Requires at least header.

The need is for consistency in showing other themes that these data are important and going to be import for theme compatibility testing in core.

[Otto42]

Patch coming tomorrow. We can get this into 5.3 since it's a non code change, and all the default themes are changing anyway. Save ourselves some future effort.

[Otto42]

Move all the relevant headers to the correct locations, standardize the format to be version numbers only, suitable for reading by code.

[Otto42]

Patch added which moves all the Requires headers to the style.css files, and removes the "WordPress" from preceding the version numbers. The "Tested up to" headers remains in the readme files, since core does not read this header.

[desrosj]

Thanks @Otto42! 48517.2.diff​ just runs the related RTL build tasks in Twenty Nineteen and Twenty Twenty to ensure the headers are fixed in the -rtl stylesheets. They are not read, but the files are direct copies with RTL transformations, so good to keep them in sync.

For Twenty Twenty, I also ​opened a PR to make the changes up stream. While development there will soon die down, I think it's good to sync that over just in case a few changes are copied back over to SVN before official release.

[desrosj]

In 46676:

Bundled Themes: Standardize the Required PHP and Tested Up To headers.

This change makes several changes to ensure consistency and accuracy for default theme headers:

• Removes WordPress from Requires at least headers.
• Ensures the Requires at least and Requires PHP headers are present in every default theme’s style.css file.
• Ensures Tested up to is present in every readme.txt file.
• Removes any headers not processed in both the style.css and readme.txt files for each theme.

Props Otto42, afragen.
Fixes #48517.

[desrosj]

Reopening to backport to 5.3.

[whyisjake]

Let's get this in 5.3.

[SergeyBiryukov]

[46676] looks good to backport, though it does feel weird to me that Requires at least and Tested up to are now defined in different files. As noted in comment:30:ticket:48515, I think it would make more sense to define them in a single place, for consistency. Even though core only reads Tested up to from the API response and not from headers at the moment, that would open such a possibility in the future. But I'll leave that for ​#meta4621.

[SergeyBiryukov]

In 46699:

Bundled Themes: Standardize the Required PHP and Tested Up To headers.

This change makes several changes to ensure consistency and accuracy for default theme headers:

• Removes WordPress from Requires at least headers.
• Ensures the Requires at least and Requires PHP headers are present in every default theme’s style.css file.
• Ensures Tested up to is present in every readme.txt file.
• Removes any headers not processed in both the style.css and readme.txt files for each theme.

Props Otto42, afragen.
Merges [46676] to the 5.3 branch.
Fixes #48517.

[SergeyBiryukov]

In 47136:

Twenty Nineteen: Standardize the Required PHP and Tested Up To headers.

• Remove WordPress from Requires at least headers.
• Ensure the Requires at least and Requires PHP headers are present in the style.css file.

Follow-up to [46676], which updated style-rtl.css, but not style.scss or style.css.

See #48517.

[SergeyBiryukov]

In 47137:

Twenty Nineteen: Standardize the Required PHP and Tested Up To headers.

• Remove WordPress from Requires at least headers.
• Ensure the Requires at least and Requires PHP headers are present in the style.css file.

Follow-up to [46676], which updated style-rtl.css, but not style.scss or style.css.

Merges [47136] to the 5.3 branch.
See #48517.