update NEWS

Author: JanMarvin

NEWS.md

@@ -6,6 +6,8 @@
 
 ## Fixes
 
+* Align the logic for writing data to empty worksheets and updating/writing to worksheets with data. This removes `update_cell_loop`()` and changes how `update_cell()` behaves. Not only does this remove duplicated code, it also brings great speed improvements (issue [356](https://github.com/JanMarvin/openxlsx2/issues/356)). [356](https://github.com/JanMarvin/openxlsx2/issues/356)
+
 * It is now possible to use special characters in formulas without coding. Previously `&` had to be encoded like `&` [251](https://github.com/JanMarvin/openxlsx2/issues/251)
 
 ## Breaking changes