Twenty Twenty-One: Standardize @since tags on "Twenty Twenty-One 1.0"

[SergeyBiryukov]

While reviewing the patch on #51919, I've noticed that Twenty Twenty-One uses a 3-digit versioning scheme 1.0.0, while other bundled themes use a 2-digit 1.X.

Per a ​quick discussion in #core-themes, the consensus was to standardize on 1.0 for consistency.

Version in style.css and Stable tag in readme.txt are already updated in [49763], this is a follow-up ticket for @since tags in PHP templates and JS files.

In addition to the above, @since tags should include the theme name, e.g. "Twenty Twenty-One 1.0", to avoid being mistakenly interpreted as "WordPress 1.0". This was previously corrected for some other bundled themes in [46827].

For future reference, the versioning scheme for bundled themes should be clarified on:

• ​https://make.wordpress.org/core/handbook/about/release-cycle/version-numbering/
• ​https://make.wordpress.org/core/handbook/about/release-cycle/update-bundled-themes/

[poena]

Replace @since

[desrosj]

In 49826:

Twenty Twenty-One: Correct @since inline documentation tags.

Previously, 1.0.0 was used for the version. This is inconsistent with the versioning used in the other default themes, which use use X.X and not X.X.X.

This change corrects all 1.0.0 occurrences to 1.0, and adds the additional context of Twenty Twenty-One to avoid confusion with WordPress 1.0.

Props SergeyBiryukov, poena.
Fixes #51958.

[desrosj]

Reopening for backport.

[desrosj]

In 49829:

Twenty Twenty-One: Correct @since inline documentation tags.

Previously, 1.0.0 was used for the version. This is inconsistent with the versioning used in the other default themes, which use use X.X and not X.X.X.

This change corrects all 1.0.0 occurrences to 1.0, and adds the additional context of Twenty Twenty-One to avoid confusion with WordPress 1.0.

Props SergeyBiryukov, poena.
Merges [49826] to the 5.6 branch.
Fixes #51958.

[desrosj]

Adding a custom keyword for querying tickets included in the Twenty Twenty-One version 1.1 release in the future.