Migrate sdl2.ext docs to inline SphinxDoc style

[a-hurst]

Currently, the primary docs for all the sdl2.ext modules are in separate .rst files instead of being in-line with their corresponding code. This makes the docs much harder to maintain, and also makes the code itself harder to read. To address this, we'll migrate the docs for these modules over to Google-style or Numpy-style inline sphinxdoc style.

Documentation to migrate

• [ ] sdl2.rst
• [x] sdl2ext.rst
• [x] sdl2ext_algorithms.rst
• [x] sdl2ext_array.rst
• [x] sdl2ext_color.rst
• [x] sdl2ext_colorpalettes.rst
• [x] sdl2ext_common.rst
• [x] sdl2ext_compat.rst
• [x] sdl2ext_draw.rst
• [ ] sdl2ext_ebs.rst
• [ ] sdl2ext_events.rst
• [x] sdl2ext_font.rst
• [ ] sdl2ext_gui.rst
• [x] sdl2ext_image.rst
• [ ] sdl2ext_particles.rst
• [x] sdl2ext_pixelaccess.rst
• [x] sdl2ext_resources.rst
• [ ] sdl2ext_sprite.rst
• [x] sdl2ext_surface.rst
• [x] sdl2ext_window.rst