[Bug] oval() does not support transparent outline
The following example (in Rust) draws an oval and a rectangle (as expected), but the oval has a dark outline:
```rust
#[no_mangle]
fn update() {
    unsafe { *DRAW_COLORS = 2 }
    oval(40, 20, 80, 40);

    unsafe { *DRAW_COLORS = 2 }
    rect(40, 80, 80, 40);
}
```
I would expect this code (and the equivalent `DRAW_COLORS = 0x02`) to draw a filled oval with no outline.

This seems to be either a bug or [the documentation](https://wasm4.org/docs/reference/functions#oval-x-y-width-height) could be more explicit, especially because [the hello world example](https://wasm4.org/docs/getting-started/hello-world#accessing-memory) also uses `DRAW_COLORS = 2`.

### Version

`w4 --version` is 2.2.0

### Workaround
Replacing `2` with `0x22` works as it draws the outline in the same color as the rest of the oval.