Unhardcoded the Bulider => we have `Can Bulid From`

Specialzation's numbers just became worse, as it refuses to specialize:
```
[warn] /mnt/data1/Work/Workspace/dev/miniboxing-plugin/tests/lib-bench/src/miniboxing/benchmarks/simple/specialized/LinkedList.scala:191: type A is unused or used in non-specializable positions.
[warn]   implicit def canBuildFrom[@specialized A]: CanBuildFrom[List[_], A, List[A]] =
[warn]                ^
[warn] one warning found
```

Oh well, I didn't include the specialization benchmarks on the webpage anyway.

Ping @MelodyLucid: You should be aware of this change