Complete structures section

COVER.md
src/SDL_SysWMEvent.3
src/SDL_SysWMInfo.3
src/SDL_SysWMmsg.3
src/SDL_TextEditingEvent.3
src/SDL_TextInputEvent.3
src/SDL_Texture.3
src/SDL_TouchFingerEvent.3
src/SDL_UserEvent.3
src/SDL_WindowEvent.3
src/SDL_assert_data.3
src/SDL_atomic_t.3
src/SDL_version.3