Add support for record constructor parameter annotations

When using C# 9 records for storage (super convenient!), you typically don't declare the properties explicitly, but leverage the concise syntax instead, so now you can do:

```
public record Book([RowKey] string ISBN, [PartitionKey] string Author, string Title);
```

Fixes #43

Author: kzu

src/TableStorage/PartitionKeyAttribute.cs

@@ -11,7 +11,7 @@ namespace Devlooped
     /// Can be applied at the class level instead with a fixed value to persist 
     /// entities with a fixed partition key value.
     /// </summary>
-    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Class)]
+    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Property | AttributeTargets.Parameter)]
     partial class PartitionKeyAttribute : TableStorageAttribute
     {
         /// <summary>

src/TableStorage/RowKeyAttribute.cs

@@ -7,9 +7,10 @@ namespace Devlooped
 {
     /// <summary>
     /// Flags the property to use as the table storage row key 
-    /// when storing the annotated type using the <see cref="TableRepository{T}"/>.
+    /// when storing the annotated type using <see cref="TableRepository{T}"/> or 
+    /// <see cref="TablePartition{T}"/>.
     /// </summary>
-    [AttributeUsage(AttributeTargets.Property)]
+    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Parameter)]
     partial class RowKeyAttribute : TableStorageAttribute
     {
         /// <summary>

src/TableStorage/TableStorageAttribute.cs

@@ -33,10 +33,23 @@ static Expression<Func<TEntity, string>> CreateGetterCore<TEntity, TAttribute>()
             var keyProp = typeof(TEntity).GetProperties()
                 .FirstOrDefault(prop => prop.GetCustomAttribute<TAttribute>() != null);
 
+            // See if the attribute is applied to a constructor argument with the same name 
+            // as a prop, like it would in a record type
+            if (keyProp == null)
+            {
+                var keyParam = typeof(TEntity).GetConstructors().SelectMany(ctor => ctor.GetParameters())
+                    .Where(prm => prm.GetCustomAttribute<TAttribute>() != null)
+                    .FirstOrDefault();
+
+                if (keyParam != null)
+                    keyProp = typeof(TEntity).GetProperties().FirstOrDefault(prop => prop.Name == keyParam.Name);
+            }
+
             if (keyProp == null)
             {
                 if (typeof(TAttribute) == typeof(PartitionKeyAttribute))
                 {
+                    // See if the attribute is applied at the class level with a fixed value
                     var partitionKey = typeof(TEntity).GetCustomAttribute<PartitionKeyAttribute>()?.PartitionKey;
                     if (partitionKey == null)
                     {

src/Tests/RepositoryTests.cs

@@ -41,6 +41,39 @@ public async Task TableEndToEnd()
                 Assert.False(true, "Did not expect to find any entities");
         }
 
+        [Fact]
+        public async Task TableRecordEndToEnd()
+        {
+            var repo = TableRepository.Create<AttributedRecordEntity>(CloudStorageAccount.DevelopmentStorageAccount);
+            var entity = await repo.PutAsync(new AttributedRecordEntity("Book", "1234"));
+
+            Assert.Equal("1234", entity.ID);
+            Assert.Null(entity.Status);
+
+            entity.Status = "Pending";
+
+            await repo.PutAsync(entity);
+
+            var saved = await repo.GetAsync("Book", "1234");
+
+            Assert.NotNull(saved);
+            Assert.Equal("Pending", saved!.Status);
+
+            var entities = new List<AttributedRecordEntity>();
+
+            await foreach (var e in repo.EnumerateAsync("Book"))
+                entities.Add(e);
+
+            Assert.Single(entities);
+
+            await repo.DeleteAsync(saved);
+
+            Assert.Null(await repo.GetAsync("Book", "1234"));
+
+            await foreach (var _ in repo.EnumerateAsync("Book"))
+                Assert.False(true, "Did not expect to find any entities");
+        }
+
         [Fact]
         public async Task DoesNotDuplicateKeyProperties()
         {
@@ -250,5 +283,11 @@ record RecordEntity(string Kind, string ID)
         {
             public string? Status { get; set; }
         }
+
+        [Table("Record")]
+        record AttributedRecordEntity([PartitionKey] string Kind, [RowKey] string ID)
+        {
+            public string? Status { get; set; }
+        }
     }
 }