@experimental without inline notice is stripped from API docs members

[pomek]

📝 Provide detailed reproduction steps (if any)

1. Add a class member with a plain @experimental annotation but without an inline Experimental: notice, for example:

   /**
    * Flag indicating whether a plugin is enabled or disabled.
    *
    * @experimental
    * @observable
    * @readonly
    */
   public declare isEnabled: boolean;

2. Build the API docs.
3. Open the generated API docs page for that member.

A concrete example can be seen in Plugin#isEnabled:

• source: packages/ckeditor5-core/src/plugin.ts
• docs page: module_core_plugin-Plugin.html

For comparison, a similar member that includes inline experimental notice text renders the badge correctly, e.g. Plugin#customExperimentalProp.

✔️ Expected result

A member explicitly annotated with @experimental should be rendered as experimental in the generated API docs, even if the JSDoc does not include an additional inline Experimental: notice in the description.

❌ Actual result

The experimental badge is not rendered for members that use only:

@experimental

without extra notice text in the summary.

In practice, this means that two members annotated with @experimental may render differently depending on whether the description also contains an inline Experimental: notice.

❓ Possible solution

The docs pipeline should preserve explicit @experimental annotations on members regardless of whether the summary contains an inline Experimental: sentence.

If there is logic intended to prevent class-level @experimental from cascading to all children, it should distinguish between:

• truly inherited/cascaded @experimental, and
• explicitly declared member-level @experimental

This is worth fixing because the current behavior is surprising for contributors, makes @experimental usage inconsistent, and causes downstream API docs tooling to render incorrect badges for valid source annotations.

📃 Other details

• Browser: N/A – build-time API docs issue
• OS: macOS
• First affected CKEditor version: latest
• Installed CKEditor plugins: N/A