Rename the public ptrace_* functions.
Rename the public ptrace_* functions.

Unlike in C, we have namespacing in Rust. Renaming the functions allows us to avoid a `use nix::sys::ptrace::*` in favor of `use nix::sys::ptrace` and then calling, for example, `ptrace::traceme()`

geofft/nix-rust,xd009642/nix,carllerche/nix-rust,nix-rust/nix,asomers/nix,Susurrus/nix,nix-rust/nix,xd009642/nix,xd009642/nix,MarkusJais/nix-rust,MarkusJais/nix-rust,geofft/nix-rust,berkowski/nix,Susurrus/nix,Susurrus/nix,asomers/nix,carllerche/nix-rust,carllerche/nix-rust,berkowski/nix,geofft/nix-rust,MarkusJais/nix-rust,berkowski/nix