This PR adds basic HTTP QUERY method support to ASP.NET Core by implementing the narrow set of APIs approved in the API review process (issue #61089).

Changes Made

HttpMethods class additions

• HttpMethods.Query: New constant for the "QUERY" HTTP method
• IsQuery(): New method to check if a string represents the QUERY method
• GetCanonicalizedValue(): Updated to support QUERY method canonicalization

Usage Example

// Check if request method is QUERY
if (HttpMethods.IsQuery(context.Request.Method))
{
    // Handle QUERY request
}

// Use the constant
var queryMethod = HttpMethods.Query; // "QUERY"

// Method canonicalization works
var canonical = HttpMethods.GetCanonicalizedValue("query"); // Returns HttpMethods.Query

API Changes

Following the approved API surface from the review:

namespace Microsoft.AspNetCore.Http;

public static class HttpMethods
{
    public static readonly string Query = "QUERY";
    
    public static bool IsQuery(string method)
    {
        return Equals(Query, method);
    }
}

Benefits

The QUERY method provides a standardized way to perform safe query operations that may require request bodies:

• Safe: Like GET, doesn't modify server state
• Cacheable: Responses can be cached
• Request body support: Unlike GET, allows complex query parameters in the request body

Testing

Comprehensive unit tests verify:

• Query method constant and IsQuery() method work correctly
• Method canonicalization properly handles QUERY variations ("QUERY", "Query", "query")
• All existing functionality remains unchanged

Fixes #61089

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