rendy: Fix a rather nasty bug in bitmap font rendering

A few commits back I introduced a bug where bitmap font rendering
would omit the first column of the rendered glyph:

We use the following code to loop over the columns in the glyph
and determine which pixels should be filled in:

```rs
for gx in 0..FONT_WIDTH {
  let draw = glyph[gy] & (1 << (FONT_WIDTH - gx)) != 0;
  // ...
}
```

And I've noticed that following code will only perform bit mask
check on bits (zero based) 1 through 8 which effectively omits
the first column of the glyph (bit 0) and checks the non existent
column 9 (bit 8).

Thanks for coming to my TED talk :^)
~~and shame on andy for not catching that (jk, it's fine!)~~

Author: 48cf

src/aero_kernel/src/rendy.rs

@@ -572,7 +572,7 @@ impl<'this> DebugRendy<'this> {
             };
 
             for gx in 0..FONT_WIDTH {
-                let draw = glyph[gy] & (1 << (FONT_WIDTH - gx)) != 0;
+                let draw = glyph[gy] & (1 << (FONT_WIDTH - gx - 1)) != 0;
                 let color = if draw {
                     char.fg
                 } else if char.bg == u32::MAX {