Blazor binding updates for 6.0

[guardrex]

• Support binding to select multiple, getting/setting the selection as an array
• Support binding to <select multiple>, getting/setting the selection as an array aspnetcore#5519

---

Document Details

⚠ Do not edit this section. It is required for docs.microsoft.com ➟ GitHub issue linking.

• ID: b211df59-e1c9-86c0-c904-31fa3c361e6d
• Version Independent ID: 3f912dfc-5ba5-6c6c-ba93-1ae78508a5cc
• Content: ASP.NET Core Blazor data binding
• Content Source: aspnetcore/blazor/components/data-binding.md
• Product: aspnet-core
• Technology: aspnetcore-blazor
• GitHub Login: @guardrex
• Microsoft Alias: riande