Fix broken docs caused by incorrect feature-scroll usage in Antora

[dmitrysulman]

There are a couple of issues with the feature-scroll attribute in the Antora docs:

• The endif::[] for the Offset-based Window table row is placed incorrectly:
  

  spring-data-commons/src/main/antora/modules/ROOT/pages/repositories/query-methods-details.adoc

  Lines 455 to 464 in f4e9581

  	ifdef::feature-scroll[]
  	| Offset-based `Window<T>`
  	| `limit + 1` at `OffsetScrollPosition.getOffset()`
  	| One to many queries fetching data starting at `OffsetScrollPosition.getOffset()` applying limiting.
  	a| A `Window` can only navigate to the next `Window`.
  	endif::[]
  	* `Window` provides details whether there is more data to fetch.
  	* Offset-based queries becomes inefficient when the offset is too large because the database still has to materialize the full result.

  
  This causes the table to break when feature-scroll is not set:

• Defining :feature-scroll: true in index.adoc has no effect because attributes set on one page are not visible to other pages. Additionally, setting the attribute value to true is redundant — ifdef blocks are evaluated based on whether the attribute is defined, regardless of its value (source).

As a result, Scroll API-related content is always hidden in the documentation.

This PR fixes the above by explicitly defining the :feature-scroll: attribute in the two pages where it's used:

• query-methods-details.adoc
• core-concepts.adoc

[dmitrysulman]

Overriding this attribute for a specific spring-data- project can be done by unsetting the attribute at the Antora playbook level.