forgetest: motion.jog-roundtrip's covers name the forgectrl route its homed-mask judge reads

The soft-reset check's reference verdict is the homed mask, read before
and after the reset through forgectrl's GET /motion/state
(cb_motion_state in src/main.c, through motion_port to the controller
port's state record), because $# prints the mask only with $22 on,
which the driver leaves off. A test that depends on a forgectrl route
names ("forgectrl", "src/main.c") in its covers, as microstep_modes
and deadman do, so that a change to the route invalidates the test's
inherited PASS. motion.jog-roundtrip's covers are now _MOTION_COVERS
plus that entry.

Proof: a compile and pyflakes 4.0.3 give no message on
forgetest/suite/motion.py, with no undefined name in forgetest or
tests. forgetest unit tests, python3 -B -m unittest discover -s tests
-p test_<name>.py, in a private PID namespace: test_manifest.py 39
OK, test_queue.py 15 OK, test_campaign.py 13 OK. Coverage lint on the
tree manifest from scripts/manifest-from-tree.py (python3 -B -m
forgetest.coverage --manifest ../tree-manifest.json --enforce):
0 uncovered, 0 empty, 0 host-tested row problems, 43 tests; the
catalog loads motion.jog-roundtrip with the five covers entries. A
host dry run of the whole test against the null-sink build of the
grblHAL-glowforge default branch head ("serial_test: the scan's exempt
arguments each match once in the sources"), with the machine side
stood in for as before and a model kernel that ramps from the
controller's cnc/stop write, passes: MPos X 3534.93 steps against
3535, tail 23% of the tick, mask 4 kept, drift 0.000 mm.

Acceptance: the covers are part of the test's own text, so the
fingerprint of motion.jog-roundtrip moves, and no other test's: of
the implementation hashes of the 43 catalog tests, before and after,
only that one differs. From here a change under forgectrl's
src/main.c invalidates motion.jog-roundtrip's inherited PASS as well.

forgetest/forgetest/suite/motion.py

@@ -194,7 +194,8 @@ def pacing(ctx):
 @test("motion.jog-roundtrip", title="Motion quality: bounded jogs, max rate, diagonal, hold/resume, "
                                    "a soft reset during a move",
       subsystem="motion", kind="auto", mode="grbl", est_min=3,
-      covers=_MOTION_COVERS, requires=["kernel.latch-locked-idle", "kernel.k1-k2"],
+      covers=_MOTION_COVERS + [("forgectrl", "src/main.c")],
+      requires=["kernel.latch-locked-idle", "kernel.k1-k2"],
       steps=["Setup: the head parked with at least 60 mm of free +X and 40 mm of free +Y travel; "
              "bed clear, lid closed."],
       description="Sanity jogs (X, Y 40 mm out/back at F2400), max-rate X out/back (60 mm at "