`looprestoration.rs`: Unsafe cleanup

[randomPoison]

There are ~50 unsafe operations happening in looprestoration.rs.

• Cleanup unsafe operations happening within functions.
• Mark any functions that can be made fully safe as such.
• Add unsafe blocks around any remaining unsafe operations along with standard safety documentation.
• Add safety documentation for functions that need to remain unsafe.
• Add #![deny(unsafe_op_in_unsafe_fn)] to file.