alias self-mutilation, self-injury -> self_harm

BUR #17067 has been approved by @nonamethanks.

create alias self-mutilation -> self_harm
create alias self-injury -> self_harm

"Self-harm, self-injury, and self-mutilation are often used interchangeably" according to this source (PDF link). The wiki for self-mutilation is practically the same as self harm. self-injury will be a utility alias.

The bulk update request #17067 (forum #242451) has been approved by @nonamethanks.

BUR #39618 has been approved by @nonamethanks.

create alias implied_self-mutilation -> implied_self-harm

At time of writing there are only 26 posts tagged implied self-mutilation, but I felt for consistency's sake this should also be aliased.

The bulk update request #39618 (forum #345811) has been approved by @nonamethanks.