Change String::toLines to use ValueOption instead of Option

[Numpsy]

If reduces memory allocations slightly

Just a thought.

Current benchmark project allocation results

| Method         | Mean     | Error   | StdDev  | Gen0       | Gen1      | Gen2      | Allocated |
|--------------- |---------:|--------:|--------:|-----------:|----------:|----------:|----------:|
| LintParsedFile | 842.2 ms | 5.43 ms | 4.81 ms | 25000.0000 | 8000.0000 | 1000.0000 | 397.55 MB |

With this change

| Method         | Mean     | Error   | StdDev  | Gen0       | Gen1      | Gen2      | Allocated |
|--------------- |---------:|--------:|--------:|-----------:|----------:|----------:|----------:|
| LintParsedFile | 837.7 ms | 4.83 ms | 4.29 ms | 25000.0000 | 8000.0000 | 1000.0000 | 396.83 MB |