Add Support of Stylus Pen for Kivy

[Sahil-pixel]

I was trying to build Kivy note taking app for Android. But for now in kivy on_touch_ e events there is no Stylus support. I saw in SDL3 there is stylus pen support. This is my request to add Stylus support for Kivy . So we can make note taking app using Kivy .

Some useful links https://github.com/libsdl-org/SDL/blob/main/include/SDL3/SDL_pen.h https://wiki.libsdl.org/SDL3/CategoryPen