Document all dataclass fields

[Hritik14]

Dataclasses expect having meaningful data and should be documented in code.
Eg:
The following should say what is expected in the aliases field.
https://github.com/nexB/vulnerablecode/blob/4390b6aca872cbde378516199f143fa11e64bc5a/vulnerabilities/importer.py#L192-L209

[BhaswatiRoy]

Hello @Hritik14
I can see 4 dataclasses in the linked file, 2 of which already has inline documentation while the other 2 doesn't.
Do we need to write inline documentation for the remaining 2 (line 54 & line 76) only?