mechanical alias

BUR #26853 has been approved by @nonamethanks.

create alias robot_legs -> mechanical_legs
create alias single_robot_leg -> single_mechanical_leg
create alias robot_hands -> mechanical_hands

There are alias for the mechanical arms tags also using robot

This bulk update request is pending automatic rejection in 5 days.

The bulk update request #26853 (forum #283139) has been approved by @nonamethanks.