Updated comment in make_stock_entry() function (#14726)

Purpose flag is used in make_stock_entry(**args) function, but it was not included in the comment inside the function.
diff --git a/erpnext/stock/doctype/stock_entry/stock_entry_utils.py b/erpnext/stock/doctype/stock_entry/stock_entry_utils.py
index 8647d0f..6b4ca18 100644
--- a/erpnext/stock/doctype/stock_entry/stock_entry_utils.py
+++ b/erpnext/stock/doctype/stock_entry/stock_entry_utils.py
@@ -20,6 +20,7 @@
 	:batch_no: Optional
 	:posting_date: Optional
 	:posting_time: Optional
+	:purpose: Optional
 	:do_not_save: Optional flag
 	:do_not_submit: Optional flag
 	'''