`LocalFileSystem.ls()` with `details=False` slow

[FrankEssenberger]

Hi fsspec developers,

I realized when using a later version of fsspec than the ones from 2023 that the .ls() was super slow. The reason came in in this issue PR: #1479 where always the info is taken for all files

and then thrown away - for a large number of files this can become costly and the detail flag can not be used to reduce work. Before the mentioned PR the os.listdir was used which just list the number of files.

I just wanted to ask if I can open a PR in which thels used the os.listdir again for detail=False and if the path is a file it will just return the path to the file - no much use to call it for a file with not details but should of cours work. And if the details=True the code stays as is?

Let me know what you think.

Best Frank