Fix missing semicolon on non-const global struct initializers

[tannergooding]

Fixes #503.

A non-const global variable initialized with a struct initializer list was emitted with a closing } but no terminating ;, which broke the rest of the generated file:

public static Point MyGlobalPoint = new Point
{
    x = 10,
    y = 20,
}   // <-- missing ';'

Root cause

CSharpOutputBuilder.EndValue only wrote the terminating semicolon for ValueKind.Unmanaged when desc.IsConstant was true. const globals (emitted as static readonly) and arrays (flagged constant via IsTypeConstantOrIncompleteArray) therefore terminated correctly, but a plain non-const global struct fell through and emitted nothing. ForRecordType had already set NeedsSemicolon, but nothing flushed it on this path.

Fix

Emit the semicolon for the non-const case as well, matching the constant branch and the Primitive/String/GuidMember value kinds.

XML output is unaffected -- XmlOutputBuilder.EndValue closes <value> unconditionally. The fix is language/platform-invariant (the struct renders identically across all C# variants), so a single ClangSharp.PInvokeGenerator.UnitTests regression test (GlobalStructInitializerTest) covers it; generate-helper-types is not involved.

Validation

• Build: 0 warnings / 0 errors (Release).
• Tests: 3709 passed, 0 failed (3708 existing byte-identical + 1 new).

Note

This PR description and the change were drafted with Copilot.