Path completion inconsistencies on Windows

[nilshg]

There's an inconsistency in how the Pkg REPL and the standard REPL mode handle patch completion on Windows:

julia 1.10> "C:/Us<tab> # autocompletes successfully to "C:/Users/

julia 1.10> "C:/Users/MyUsername/OneD<tab> # autocompletes successfully to "C:/Users/MyUsername/OneDrive - MyCompany/

(@v1.10) pkg> activate "C:/Us<tab> # nothing

(@v 1.10) pkg> activate C:/Us<tab> # completes to C:/Users\\

(@v1.10) pkg> activate C:/Users/MyUsername/OneD<tab> # nothing

so in 1.10, regular path completion is working entirely fine in the normal REPL, but the Pkg REPL can't seem to deal with paths with spaces. In addition, the regular REPL only autocompletes paths when there's a leading ", while the Pkg REPL only completes paths when there's no leading ", which is a bit confusing as to activate paths with spaces one actually does need to enclose the path in quotes.

In 1.12 the behaviour is basically the same, except we now also have in the regular REPL:

julia 1.12> "C:/Us<tab> # autocompletes to "C:/\\Users\\, which amazingly seems to be a valid path!?!

Which I would consider a regression despite the paths apparently working.