Added event handling support to VisNetwork and enhanced component documentation

src/myfasthtml/controls/FileUpload.py

@@ -35,6 +35,14 @@ class Commands(BaseCommands):
 
 
 class FileUpload(MultipleInstance):
+  """
+  Represents a file upload component.
+
+  This class provides functionality to handle the uploading process of a file,
+  extract sheet names from an Excel file, and enables users to select a specific
+  sheet for further processing. It integrates commands and state management
+  to ensure smooth operation within a parent application.
+  """
   
   def __init__(self, parent, _id=None):
     super().__init__(parent, _id=_id)