function Deno.realPath
realPath(path: string | URL): Promise<string>
Resolves to the absolute normalized path, with symbolic links resolved.
```ts
// e.g. given /home/alice/file.txt and current directory /home/alice
await Deno.symlink("file.txt", "symlink_file.txt");
const realPath = await Deno.realPath("./file.txt");
const realSymLinkPath = await Deno.realPath("./symlink_file.txt");
console.log(realPath); // outputs "/home/alice/file.txt"
console.log(realSymLinkPath); // outputs "/home/alice/file.txt"
```
Requires `allow-read` permission for the target path.
Also requires `allow-read` permission for the `CWD` if the target path is
relative.
Promise<string>