add xml comments for IValueTypeDiscriminator

Author: JJ11teen

YamlDotNet/Serialization/BufferedDeserialization/TypeDiscriminators/IValueTypeDiscriminator.cs

@@ -3,10 +3,28 @@
 
 namespace YamlDotNet.Serialization.BufferedDeserialization.TypeDiscriminators
 {
+    /// <summary>
+    /// An ITypeDiscriminator provides an interface for discriminating which dotnet type to deserialize a yaml
+    /// stream into. They require the yaml stream to be buffered <see cref="BufferedNodeDeserializer" /> as they
+    /// can inspect the yaml value, determine the desired type, and reset the yaml stream to then deserialize into
+    /// that type.
+    /// </summary>
     public interface ITypeDiscriminator
     {
+        /// <summary>
+        /// Gets the BaseType of the discriminator. All types that an ITypeDiscriminator may discriminate into must
+        /// inherit from this type. This enables the deserializer to only buffer values of matching types.
+        /// If you would like an ITypeDiscriminator to discriminate all yaml values, the BaseType will be object.
+        /// </summary>
         Type BaseType { get; }
 
+        /// <summary>
+        /// Trys to discriminate a type from the current IParser. As discriminating the type will consume the parser, the
+        /// parser will usually need to be a buffer so an instance of the discriminated type can be deserialized later.
+        /// </summary>
+        /// <param name="buffer">The IParser to consume and discriminate a type from.</param>
+        /// <param name="suggestedType">The output type discriminated. Null if no type matched the discriminator.</param>
+        /// <returns>Returns true if the discriminator matched the yaml stream.</returns>
         bool TryDiscriminate(IParser buffer, out Type? suggestedType);
     }
 }