glGetString should return a [*:0]u8

[eddineimad0]

zigwin32/win32/graphics/open_gl.zig

Lines 2060 to 2062 in 4a78e71

	pub extern "opengl32" fn glGetString(
	name: u32,
	) callconv(@import("std").os.windows.WINAPI) ?*u8;