Allow max number of files used by file_picker to be configurable

[nstinus]

It is currently an undocumented hard coded value. Allowing it to be configurable has the benefit of documenting it and allowing users to set a greater value. Perhaps with a warning that bad performance could be expected?

helix/helix-term/src/ui/mod.rs

Line 214 in 012fc12

const MAX: usize = 100_000;

[pascalkuthe]

This was adreased by #7814, there is no limit anymore, files are streamed into the picker in the background now (and the matcher ks fast enough to handle millions of files)