tests(g28.2): drop a stale commit hash from the sequencing test comment

The rebase onto current master rewrote every commit hash on this branch, so
the "65447329e9" reference in sequencing/test-ui.py no longer resolves.
Describe the behaviour under test instead.

Author: greatEndian

tests/interp/g28.2/sequencing/test-ui.py

@@ -82,9 +82,10 @@ def near(a, b, tol=0.001):
     fail("task_mode changed across a redundant G28.2 Pn: {} -> {}".format(mode_before, s.task_mode))
 print("PASS: G28.2 Pn's mode dip is invisible at the task level")
 
-# The machine is fully homed, so this passes the NO_FORCE_HOMING gate and
-# reaches the actual Pn validation, which must reject joint 99 without
-# leaving task_mode stuck (regression test for the fix in 65447329e9).
+# The machine is fully homed, so this reaches the actual Pn validation,
+# which must reject joint 99 without leaving task_mode stuck: an
+# outright-rejected home must still undo the FREE-mode dip (fix(g28):
+# "restore traj mode when G28.2 rejects the request outright").
 c.mdi("G28.2 P99")
 if not wait_idle():
     fail("invalid-joint G28.2 P99 did not settle")