How to change default Font in Bevy

On my project I wan to use a different default font to have more special characters.
I want to embed this font in my binary.

On v0.18 I used to change default font by using something like that:

```rust
const FIRA_MONO_FONT: &[u8] = include_bytes!("../assets/fonts/FiraMono-Medium.ttf");

let font = Font::try_from_bytes(FIRA_MONO_FONT.to_vec()) .expect("Failed to load embedded font");

font_assets.insert(TextFont::default().font.id(), font).expect("Impossible to change default font");
```

On v0.19 it's not possible to do: ```TextFont::default().font.id()```

What is the best way to override Default font ?

Start with the Bevy 0.19 TextFont API and the font_assets insertion approach shown in the issue, comparing it with the v0.18 example. Confirm the supported way to embed and select a replacement default font, then document a working example and verify that special characters render correctly.

Written by the indexing model from the issue text.