Change mjVISSTRING of connect and weld equality constraints from "Constraint" to "Equality". This is more consistent with the 'E' shortcut key and with mjDISABLESTRING ("constraint" means all constraints, "equality" means bilateral constraints).

Also remove unused ampersands from `mjVISSTRING` names, these are a remnant from a very old version of the UI framework.

PiperOrigin-RevId: 593469811
Change-Id: I0f6f73c9f5d2c61b2280f395f76434b0710ce4f3

python/mujoco/bindings_test.py

@@ -822,7 +822,7 @@ Euler integrator, semi-implicit in velocity.
     self.assertLen(mujoco.mjRNDSTRING, mujoco.mjtRndFlag.mjNRNDFLAG)
     self.assertEqual(mujoco.mjDISABLESTRING[11], 'Refsafe')
     self.assertEqual(mujoco.mjVISSTRING[mujoco.mjtVisFlag.mjVIS_INERTIA],
-                     ('&Inertia', '0', 'I'))
+                     ('Inertia', '0', 'I'))
 
   def test_enum_values(self):
     self.assertEqual(mujoco.mjtJoint.mjJNT_FREE, 0)