add unit test for stop() method

[prjemian]

apstools/apstools/devices/positioner_soft_done.py

Lines 197 to 202 in 7645cf1

	def stop(self, *, success=False):
	"""
	Hold the current readback when stop() is called and not :meth:`inposition`.
	"""
	if not self.inposition:
	self.setpoint.put(self.position)

[prjemian]

Also add self.stop = self.temperature.stop to each linkam's __init__() method.

@ilavsky, Thanks for the suggestion!

[prjemian]

Re-opening since related workflow still fails.