Remove note that 404 response code means succes

[jnoordsij]

Description

Looking into the documentation on handling responses, I found a note on IsSuccessfulStatusCode mentioning "that 404 response code means succes". However, when checking implementation and tests, I found only that ResponseStatus will be Completed on 404 responses, but IsSuccessfulStatusCode should be false.

See also:

• https://learn.microsoft.com/en-us/dotnet/api/system.net.http.httpresponsemessage.issuccessstatuscode?view=net-9.0

• RestSharp/src/RestSharp/Options/RestClientOptions.cs

  Lines 57 to 63 in 58180e8

  	/// <summary>
  	/// Function to calculate the response status. By default, the status will be Completed if it was successful, or NotFound.
  	/// </summary>
  	public CalculateResponseStatus CalculateResponseStatus { get; set; } = httpResponse
  	=> httpResponse.IsSuccessStatusCode || httpResponse.StatusCode == HttpStatusCode.NotFound
  	? ResponseStatus.Completed
  	: ResponseStatus.Error;

• RestSharp/test/RestSharp.Tests.Integrated/StatusCodeTests.cs

  Lines 68 to 75 in 58180e8

  	[Fact]
  	public async Task Reports_4xx_Status_Code_Success_Accurately() {
  	var request = new RestRequest("404");
  	var response = await _client.ExecuteAsync(request);
  	response.IsSuccessful.Should().BeFalse();
  	response.IsSuccessStatusCode.Should().BeFalse();
  	}

Purpose

This pull request is a:

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)