Support F# files (.fs) for nesting

[2moveit]

FileNesting supports many languages but in a F# project it does not work. It would be really great to nest e.g. .resx files under .fs files. Currently the menu entries "Nest item..." and "Un-nest item" are disabled.

I think it's just because it is not in the allowed list in the PathSegmentFileNester.cs. So it might be quite easy to support.

Maybe it is worth to support .fsx files (script files) too. But for automatic the priority usually is for .fs files.

[cmeeren]

I too would very much like to see this.