Fix type completion in static contexts for primary constructors

[akhera99]

Fixes: #82750

Restores type suggestions hidden by same name primary constructor parameters in static contexts

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Pull request overview

This PR updates C# symbol recommendation logic to ensure namespaces/types are still suggested in static contexts when same-named primary-constructor parameters are returned by static-member lookup and would otherwise hide those candidates during completion.

Changes:

• Adjust symbol lookup in static expression/statement contexts to re-add namespace/type candidates matching primary-constructor parameter names.
• Add a regression completion test covering the reported static-context scenario.

Show a summary per file

File	Description
src/Workspaces/CSharp/Portable/Recommendations/CSharpRecommendationServiceRunner.cs	Augments static-context symbol lookup to recover namespace/type candidates hidden by primary-constructor parameters.
src/EditorFeatures/CSharpTest/Completion/CompletionProviders/SymbolCompletionProviderTests.cs	Adds a regression test ensuring the type is suggested in the reported static-context scenario.

Copilot's findings

• Files reviewed: 2/2 changed files
• Comments generated: 1

[Copilot]

Copilot's findings

• Files reviewed: 2/2 changed files
• Comments generated: 0 new

[Copilot]

Copilot's findings

Suppressed comments (1)

src/Workspaces/CSharp/Portable/Recommendations/CSharpRecommendationServiceRunner.cs:421

• parameter.IsPrimaryConstructor(_cancellationToken) in this completion hot path calls into DeclaringSyntaxReferences[0].GetSyntax(...) and compares syntax nodes. Since you only need to know whether the containing constructor is a primary constructor, you can avoid those syntax materializations by using IMethodSymbolExtensions.IsPrimaryConstructor() on parameter.ContainingSymbol instead.

                            if (symbol is IParameterSymbol parameter && parameter.IsPrimaryConstructor(_cancellationToken))
                            {
                                staticSymbols.AddRange(semanticModel.LookupNamespacesAndTypes(position, name: parameter.Name));

• Files reviewed: 2/2 changed files
• Comments generated: 0 new