The helper `KSPe.IO.Hierarchy.SAVE.Solve()` is botched!

[Lisias]

That's the history:

Historically, KSPe.IO.Hierarchy.<SOMETHING>.Solve() and KSPe.IO.Hierarchy.<SOMETHING>.Solve(<filename>) matches, with .Solve(<filename>) resolving into a path those directory matches Solve().

BUT...

Due the changes needed by that crappy half-baked workaround to bypass PD-Launcher (let it rot in Hell), I ended up reworking heavily these helpers, and apparently I left some edges to be trimmed.

Task: KSPe.IO.Hierarchy.<SOMETHING>.Solve() should behave exactly like System.IO.Path.GetDirectoryName(KSPe.IO.Hierarchy.<SOMETHING>.Solve(<filename>).