fix: parameter description

Co-authored-by: Shumpei Wakabayashi <42209144+shmpwk@users.noreply.github.com>

Author: satoshi-ota

planning/behavior_path_avoidance_module/config/avoidance.param.yaml

@@ -208,9 +208,9 @@
           max_right_shift_length: 5.0
           max_left_shift_length: 5.0
           max_deviation_from_lane: 0.5                  # [m]
-          # approve next shift line after reaching this percentage of current shift line length.
-          # this param is added so that it can wait return shift approval until the behind occlusion of avoid target is clear.
-          # it's able to disable this feature by setting this param 0.0.
+          # approve the next shift line after reaching this percentage of the current shift line length.
+          # this parameter is added to allow waiting for the return of shift approval until the occlusion behind the avoid target is clear.
+          # this feature can be disabled by setting this parameter to 0.0.
           ratio_for_return_shift_approval: 0.5          # [-]
         # avoidance distance parameters
         longitudinal: