tmc: Enable sg_angle_offset for smooth switching from Stealthchop to Spreadcycle (#6123)

Signed-off-by: Alan.Ma from BigTreeTech <tech@biqu3d.com>

docs/Config_Reference.md

@@ -3410,6 +3410,7 @@ run_current:
 #driver_SEDN: 0
 #driver_SEIMIN: 0
 #driver_SFILT: 0
+#driver_SG4_ANGLE_OFFSET: 1
 #   Set the given register during the configuration of the TMC2240
 #   chip. This may be used to set custom motor parameters. The
 #   defaults for each parameter are next to the parameter name in the

klippy/extras/tmc2240.py

@@ -394,6 +394,8 @@ class TMC2240:
         set_config_field(config, "pwm_lim", 12)
         #   TPOWERDOWN
         set_config_field(config, "tpowerdown", 10)
+        #   SG4_THRS
+        set_config_field(config, "sg4_angle_offset", 1)
 
 def load_config_prefix(config):
     return TMC2240(config)