Review open_file_box (Internal use only)

Implementation

• Updating src/xtd.forms/include/xtd/forms/save_file_box.h to add .file_name(output) to set the specified user file name.

Example

• Updating examples/xtd.forms.examples/save_file_box/src/save_file_box.cpp add file_name = "MyFile.txt"
• Updating examples/xtd.forms.examples/README.md to add save_file_box example.

Documentaton