function Deno.copyFileSync
copyFileSync(fromPath: string | URL,toPath: string | URL,): void
Synchronously copies the contents and permissions of one file to another
specified path, by default creating a new file if needed, else overwriting.
Fails if target path is a directory or is unwritable.
```ts
Deno.copyFileSync("from.txt", "to.txt");
```
Requires `allow-read` permission on `fromPath`.
Requires `allow-write` permission on `toPath`.
void