Document EF Core 11 FullJoin support

[roji]

EF Core 11 now translates the new .NET 11 FullJoin LINQ operator, so the EF Core 11 release notes should cover the feature and the SQL Server hybrid search guidance can use it instead of documenting a workaround.

This updates the EF Core 11 whats-new page with a FullJoin example and adds a SQL Server hybrid search subsection under full-text search improvements. It also updates the SQL Server vector search hybrid search example to use FullJoin, including null-aware scoring for results that appear on only one side of the search.

Validation: npx --yes markdownlint-cli entity-framework/core/what-is-new/ef-core-11.0/whatsnew.md entity-framework/core/providers/sql-server/vector-search.md

[Copilot]

Pull request overview

This PR updates the EF Core 11 documentation to cover new LINQ FullJoin translation support and to modernize the SQL Server hybrid (full-text + vector) search guidance by using FullJoin instead of a LeftJoin workaround.

Changes:

• Add an EF Core 11 release-notes entry demonstrating translation of the .NET 11 FullJoin LINQ operator to FULL JOIN.
• Add a “Hybrid search” subsection under SQL Server full-text search improvements in EF Core 11 release notes, referencing the vector search docs.
• Update the SQL Server vector search hybrid search example to use FullJoin and include null-aware scoring when a result appears on only one side.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
entity-framework/core/what-is-new/ef-core-11.0/whatsnew.md	Adds FullJoin documentation and introduces a SQL Server hybrid search subsection in EF Core 11 release notes.
entity-framework/core/providers/sql-server/vector-search.md	Updates the hybrid search example/query and corresponding SQL output to use FullJoin with null-aware scoring.