Constant value delimiter for directory option for bucket.getFiles

[kolban-google]

I was studying bucket.getFiles() options and found a property called "directory". I couldn't understand what this did or how it should work so I examined the source code and came to this source:

https://github.com/googleapis/nodejs-storage/blob/master/src/bucket.ts#L2234

at that location, we find the implementation of the directory option property. If I am reading it correctly, it appears to assume that the delimiter will be fixed to be '/'. While I fully agree that I can't imagine anyone wanting a delimiter other than this, our documentation does allow for arbitrary delimiters as specified by the delimiter option. This report asks for y'all to consider whether or not the "directory" option needs to consider the value that the programmer passed in for "delimiter".