imply cable_tail -> mechanical_tail

BUR #8939 has been approved by @nonamethanks.

create implication cable_tail -> mechanical_tail

Noticed someone mass removing mechanical tail from cable tails. Cable tails are a subset of robot/mechanical tails, they should not be a separate category when mechanical tail just means a tail that is mechanical in nature.

The annoying thing is, most of the affected posts were tagged mechanical_tail long before the cable_tail tag even existed. No one has ever come to the forum expressing a problem with them being tagged mechanical_tail. Mass-removing the tag without warning like this is uncalled for.

The bulk update request #8939 (forum #205889) has been approved by @nonamethanks.

When I wrote the wiki for cable_tail, I had indicated that the two tags were distinct, with only minor overlap, due to my personal interpretation of the word "mechanical" (which turned out to differ from a dictionary definition). That was my reasoning for removing the mechanical_tail tag en masse. As that interpretation still remained in the wiki until today, I have now updated it to reflect that cable tails are to be considered a subset of mechanical tails. I will remember that mass edits should be discussed in the forum first, even if the wiki is clear on the matter.