Make Grabber add a _ after illegal folder names

[Vike91]

Is your feature request related to a problem? Please describe

When saving images in folders (ex. by artist), you sometimes get an artist name that is actually an illegal Windows folder name, thus halting the download.
Illegal folder names:

Describe the solution you'd like

Make Grabber add a _ after the name in this case.

Describe alternatives you've considered

To just put all images in one folder, regardless of artist.

[Bionus]

Do you have an example of illegal folder name that doesn't work?

Because Grabber already has this logic, although it adds a ! rather than a _:

imgbrd-grabber/src/lib/src/functions.cpp

Lines 611 to 612 in 7bdb03b

	// Fobidden directories or filenames
	static const QStringList forbidden { "CON", "PRN", "AUX", "NUL", "COM1", "COM2", "COM3", "COM4", "COM5", "COM6", "COM7", "COM8", "COM9", "LPT1", "LPT2", "LPT3", "LPT4", "LPT5", "LPT6", "LPT7", "LPT8", "LPT9" };

imgbrd-grabber/src/lib/src/functions.cpp

Lines 629 to 631 in 7bdb03b

	if (invalidChars && forbidden.contains(part)) {
	part = part + "!";
	}

imgbrd-grabber/src/tests/src/functions-test.cpp

Line 100 in 7bdb03b

assertFixFilename(0, "COM1\\image.jpg", "C:\\test\\", "COM1!\\image.jpg");

[Vike91]

From https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file

`Do not use the following reserved names for the name of a file:

CON, PRN, AUX, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, and LPT9. `