Some processes use very naive string matching when detecting extensions, for example, Cossacks III checks if the extension is "contained" in the current extension is checking, causing that `WGL_ARB_pixel_format` is contained in `WGL_ARB_pixel_format_float`, but it ends up with the flag deactivated because they aren't the same.
This makes it consistent with the behavior on winemac.drv/opengl.c too.
-- v2: winex11.drv: Change order register_extension for WGL_ARB_pixel_format_float.