Moved all extension methods into extension blocks (#1155)

app/MindWork AI Studio/Chat/SetFileAttachmentExtensions.cs

@@ -2,20 +2,23 @@ namespace AIStudio.Chat;
 
 public static class SetFileAttachmentExtensions
 {
-    /// <summary>
-    /// Attaches a file in place of the attachment of the same file the set held before.
-    /// </summary>
-    /// <remarks>
-    /// The attachments differ by more than their files: one of a message being edited holds the
-    /// entry of the text it was sent with, and the size of the file may have changed since. Both
-    /// would stay in the set, and the message would go with the old and the new text of the file.
-    /// Attaching a file again means the file as it is now.
-    /// </remarks>
     /// <param name="attachments">The attachments of a message.</param>
-    /// <param name="attachment">The attachment of the file just attached.</param>
-    public static void AttachInPlaceOfSameFile(this HashSet<FileAttachment> attachments, FileAttachment attachment)
+    extension(HashSet<FileAttachment> attachments)
     {
-        attachments.RemoveWhere(existing => string.Equals(existing.FilePath, attachment.FilePath, StringComparison.Ordinal));
-        attachments.Add(attachment);
+        /// <summary>
+        /// Attaches a file in place of the attachment of the same file the set held before.
+        /// </summary>
+        /// <remarks>
+        /// The attachments differ by more than their files: one of a message being edited holds the
+        /// entry of the text it was sent with, and the size of the file may have changed since. Both
+        /// would stay in the set, and the message would go with the old and the new text of the file.
+        /// Attaching a file again means the file as it is now.
+        /// </remarks>
+        /// <param name="attachment">The attachment of the file just attached.</param>
+        public void AttachInPlaceOfSameFile(FileAttachment attachment)
+        {
+            attachments.RemoveWhere(existing => string.Equals(existing.FilePath, attachment.FilePath, StringComparison.Ordinal));
+            attachments.Add(attachment);
+        }
     }
 }