Name enhancement erasion_op => absorbing_op

[Kannen]

There is the identity_op lint that fires on operations as 1*x

The name identity correspond to the accepted term, see Wikipedia/identity element.

There is the erasing_op lint that fires on operations as 0*x
But the term erasing is vague, e.g.: could it mean type erasure??
There is a precise word for that too: 0 is an absorbing element: see Wikipedia/absorbing element

[HKalbasi]

@giraffate any disagreement? How much harm does renaming a lint?

[giraffate]

No, I just wanted some more opinions about this.

[HKalbasi]

#2845 suggest merging those and some more lints to unused_operations. I think unnecessary_operation is a better name for that merged lint but this is already a lint which is completely different.