Unclosed string breaks `overlay use`

Describe the bug

When the overlay file that is being used has a string that is unclosed, overlay use waits for more input.

How to reproduce

1. Create a file, foo.nu with the following contents:

   const value = "This string is unclosed
   

2. Use the file as an overlay with overlay use foo.nu

Expected behavior

When I run overlay use foo.nu, I expect to get an error message saying that the string is unclosed. However, instead it just prompts for more input:

~> overlay use foo.nu
::: 
::: 
::: 

Only Ctrl-C will close it, but it won't add the overlay.

Screenshots

Configuration

~> version | transpose key value | to md --pretty
| key                | value                                     |
| ------------------ | ----------------------------------------- |
| version            | 0.87.0                                    |
| branch             |                                           |
| commit_hash        |                                           |
| build_os           | linux-x86_64                              |
| build_target       | x86_64-unknown-linux-gnu                  |
| rust_version       | rustc 1.73.0 (cc66ad468 2023-10-03)       |
| rust_channel       | stable-x86_64-unknown-linux-gnu           |
| cargo_version      | cargo 1.73.0 (9c4383fb5 2023-08-26)       |
| build_time         | 2023-11-16 17:30:33 -07:00                |
| build_rust_channel | release                                   |
| allocator          | mimalloc                                  |
| features           | default, extra, sqlite, trash, which, zip |
| installed_plugins  |                                           |

Additional context

No response

Reproduce the issue with a foo.nu file containing the unclosed string shown in the report, then run overlay use foo.nu. Trace the overlay-use parsing path and the handling of incomplete input; done means the command reports an unclosed-string error instead of prompting for more input.