chore: remove unused update_log_for_doc_creation flag

* chore: add note/warning for log_types

frappe/model/__init__.py

@@ -114,6 +114,8 @@ core_doctypes_list = (
 	"Client Script",
 )
 
+# NOTE: this is being used for dynamic autoincrement in new sites,
+# removing any of these will require patches.
 log_types = (
 	"Version",
 	"Error Log",

frappe/model/document.py

@@ -275,9 +275,6 @@ class Document(BaseDocument):
 		if self.get("amended_from"):
 			self.copy_attachments_from_amended_from()
 
-		# flag to prevent creation of event update log for create and update both
-		# during document creation
-		self.flags.update_log_for_doc_creation = True
 		self.run_post_save_methods()
 		self.flags.in_insert = False