-----Description-----
This task requires writing a Lean 4 method that removes all occurrences of a given element from a list of natural numbers. The method should return a new list that contains all the elements of the original list except those equal to the target number. The order of the remaining elements must be preserved.

-----Input-----
The input consists of two elements:
lst: A list of natural numbers (List Nat).
target: A natural number to be removed from the list.

-----Output-----
The output is a list of natural numbers:
Returns a new list with all occurrences of the target number removed. The relative order of the remaining elements must be the same as in the input list.

