fix type accesssibility

Author: smdn

src/Smdn.Devices.BP35XX/Smdn.Devices.BP35XX/BP35A1.cs

@@ -84,7 +84,7 @@ private BP35A1(
   {
   }
 
-  private protected class BP35A1SerialPortStreamFactory(BP35A1Configurations configurations) : SerialPortStreamFactory {
+  private class BP35A1SerialPortStreamFactory(BP35A1Configurations configurations) : SerialPortStreamFactory {
     public override BP35UartBaudRate BaudRate { get; } = configurations.BaudRate;
     public override bool UseFlowControl { get; } = configurations.UseFlowControl;
   }

src/Smdn.Devices.BP35XX/Smdn.Devices.BP35XX/BP35Base.SerialPortStreamFactory.cs

@@ -10,7 +10,7 @@ namespace Smdn.Devices.BP35XX;
 #pragma warning disable IDE0040
 partial class BP35Base {
 #pragma warning restore IDE0040
-  private protected abstract class SerialPortStreamFactory : IBP35SerialPortStreamFactory {
+  internal abstract class SerialPortStreamFactory : IBP35SerialPortStreamFactory {
     public abstract BP35UartBaudRate BaudRate { get; }
     public abstract bool UseFlowControl { get; }