Accept umlauts in filenames via output patterns

[ediweissmann]

Use-case is a split by text where the [TEXT] placeholder is populated with names with umlauts (eg: Süßger).

The expectation is the output filename is Süßger.pdf, when pattern is [TEXT].pdf.
At the moment we strip out the umlaut, should be able to keep since they are most likely valid in pathnames.