docs: anna sig stuff helpers

Dalamud/Utility/Signatures/Wrappers/IFieldOrPropertyInfo.cs

@@ -2,16 +2,38 @@ using System;
 
 namespace Dalamud.Utility.Signatures.Wrappers
 {
+    /// <summary>
+    /// Interface providing information about a field or a property.
+    /// </summary>
     internal interface IFieldOrPropertyInfo
     {
+        /// <summary>
+        /// Gets the name of the field or property.
+        /// </summary>
         string Name { get; }
 
+        /// <summary>
+        /// Gets the actual type of the field or property.
+        /// </summary>
         Type ActualType { get; }
 
+        /// <summary>
+        /// Gets a value indicating whether or not the field or property is nullable.
+        /// </summary>
         bool IsNullable { get; }
 
+        /// <summary>
+        /// Set this field or property's value.
+        /// </summary>
+        /// <param name="self">The object instance.</param>
+        /// <param name="value">The value to set.</param>
         void SetValue(object? self, object? value);
 
+        /// <summary>
+        /// Get a custom attribute.
+        /// </summary>
+        /// <typeparam name="T">The type of the attribute.</typeparam>
+        /// <returns>The attribute.</returns>
         T? GetCustomAttribute<T>() where T : Attribute;
     }
 }