Add note on breaking change

Thomas Lemon · Thomas Lemon · commit 4fdb97b605c7 · 2026-02-11T15:54:47.000-08:00
diff --git a/docs/changes/newsfragments/7851.improved_driver b/docs/changes/newsfragments/7851.improved_driver
@@ -1,2 +1,3 @@
 Refactored ``Keithley2600`` driver to use `ParameterWithSetpoints` instead
-of relying on deprecated `qcodes_loop` code.
+of relying on deprecated `qcodes_loop` code. Contains breaking change since
+method `doFastSweep` has been replaced with `fastweep`.
