Modalities expects JSONL to have a trailing \n for the last JSON document (best practice but not guaranteed by JSONL file format)聽#395
Description
System Info
current master version (cb096c2) and probably all previous versions.
馃悰 Describe the bug
Modalities currently expects that each JSONL file ends with a trailing \n.
While a trailing \nafter all JSONs is best practice, it is not enforced by the JSONL format that also the last JSON ends with \n.
Including a line terminator after the last JSON value in a file is strongly recommended but not required.
In Modalities, this can lead to e.g., two documents getting concatenated when shuffling (last document + some non-last document). For large files, this is probably negligible ... but for consistency, we should fix this issue.