Clarify that collection expressions don't support inline arrays

[Copilot]

The collection expressions documentation was causing confusion about whether inline arrays are supported. Users reported getting CS9174 errors when trying to use collection expressions with inline arrays, which is the expected behavior since inline arrays are not supported for collection expressions in C# 12.

The issue was that the conversions section mentioned "Arrays" generically, which could be interpreted to include inline arrays. This change clarifies the documentation by:

1. Specifying regular arrays explicitly - Changed "Arrays" to "Arrays, such as int[] or string[]" to make it clear we're referring to standard arrays
2. Adding explicit clarification - Added a NOTE section stating that collection expressions cannot be used to initialize inline arrays and that inline arrays require different initialization syntax
3. Providing helpful cross-reference - Linked to the inline arrays documentation for users who need to learn about proper inline array initialization

The change is minimal and surgical, only adding clarification without changing any existing functionality or breaking any links. Testing confirmed that:

• Regular arrays continue to work correctly with collection expressions
• Inline arrays still produce CS9174 as expected when used with collection expressions
• The documentation links resolve properly

Fixes #38916.

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docs/csharp/language-reference/operators/collection-expressions.md	docs/csharp/language-reference/operators/collection-expressions

[BillWagner]

This is ready for final review.