Mouse 4 as back

Adds a new keybind that makes you go back to the previous screen.

It has 4 ways of finding the previous screen.

It first tries to find any buttons on screen that in the en_us language, has any of these words as its title: back, return, done, cancel. If it finds any button that only contain one of those words, then it will click that.

If that fails, it tries to check the screen class. Some screens store a variable to remember the previous screen it was on. Think going from the video settings subscreen back to the settings screen. The mod tries to find any field that is named the following:
previous, previousscreen, lastscreen, parent, parentscreen. These variable names are taken from any vanilla screen class I can find. If you have suggestions of ones to add then im all ears.

If that fails. It tries to go to the extending class. Some classes extend other classes and the class they extend may store a variable to the previous screen. So it tries to search with a depth of 7, arbitrarily chosen, and does the field technique described above.

If all of that fails, it tries calling the close method, basically just pressing escape.

If you are for some reason wondering, as a mod dev, on how to make sure this mod works. Then just simple have either a button that only has the text being: back, return, done, cancel. Or store a previous screen variable as previous, lastscreen, previousscreen, parent, parentscreen