Function mutate_path_prefix 

pub fn mutate_path_prefix(
    path_and_query: &str,
    strategy: PathPrefixStrategy,
) -> (String, &'static str)

Apply a path-prefix mutation to a path-and-query string. Returns the mutated form and the technique label.

Wraps PathPrefixStrategy::apply with the label that the gene-bank and --techniques flag downstream consume.