Inheritance of formatconfig

[jnyrup]

If possible, it would be nice to support inheritance for .formatconfig.

while .formatconfig contains no root, root = false and is not located in root of drive, search in parent folder for a .formatconfig.

This gives a inheritance chain of config files.

To compute the final formatting settings, start with most parent file and apply the more specific format settings.

Note that allowed_extensions and denied_extensions are sets and not simple on/off switches, so it would be nice to have special operators to handle them.

denied_extensions = .cs # <-- completely override settings from parent file(s)
denied_extensions -= .cs # <-- settings from parent file(s) except .cs
denied_extensions += .cs # <-- settings from parent file(s) and additionally .cs

Also, if possible, it would be nice if e.g. a single subfolder within a solution can have its own .formatconfig.