impl From<String> and From<&str> for TextSection (bevyengine#8856)

# Objective

Implement `From<String>` and `From<&str>` for `TextSection`

Example from something I was working on earlier:
```rust
parent.spawn(TextBundle::from_sections([
    TextSection::new("press ".to_string(), TextStyle::default()),
    TextSection::new("space".to_string(), TextStyle { color: Color::YELLOW, ..default() }),
    TextSection::new(" to advance frames".to_string(), TextStyle::default()),
]));
```

After an `impl From<&str> for TextSection` :

```rust
parent.spawn(TextBundle::from_sections([
    "press ".into(),
    TextSection::new("space".to_string(), TextStyle { color: Color::YELLOW, ..default() }),
    " to advance frames".into(),
]));
```

* Potentially unhelpful without a default font, so behind the
`default_font` feature.

 Co-authored-by: [hate](https://github.com/hate)

---------

Co-authored-by: hate <15314665+hate@users.noreply.github.com>

crates/bevy_text/src/text.rs

@@ -139,6 +139,26 @@ impl TextSection {
     }
 }
 
+#[cfg(feature = "default_font")]
+impl From<&str> for TextSection {
+    fn from(value: &str) -> Self {
+        Self {
+            value: value.into(),
+            ..default()
+        }
+    }
+}
+
+#[cfg(feature = "default_font")]
+impl From<String> for TextSection {
+    fn from(value: String) -> Self {
+        Self {
+            value,
+            ..Default::default()
+        }
+    }
+}
+
 /// Describes horizontal alignment preference for positioning & bounds.
 #[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Hash, Reflect, Serialize, Deserialize)]
 #[reflect(Serialize, Deserialize)]

crates/bevy_ui/src/node_bundles.rs

@@ -268,6 +268,15 @@ impl TextBundle {
     }
 }
 
+impl<I> From<I> for TextBundle
+where
+    I: Into<TextSection>,
+{
+    fn from(value: I) -> Self {
+        Self::from_sections(vec![value.into()])
+    }
+}
+
 /// A UI node that is a button
 #[derive(Bundle, Clone, Debug)]
 pub struct ButtonBundle {

examples/ui/text.rs

@@ -45,11 +45,12 @@ fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
         .with_style(Style {
             position_type: PositionType::Absolute,
             bottom: Val::Px(5.0),
-            right: Val::Px(15.0),
+            right: Val::Px(5.0),
             ..default()
         }),
         ColorText,
     ));
+
     // Text with multiple sections
     commands.spawn((
         // Create a TextBundle that has a Text with a list of sections.
@@ -63,15 +64,55 @@ fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
                     color: Color::WHITE,
                 },
             ),
-            TextSection::from_style(TextStyle {
-                font_size: 60.0,
-                color: Color::GOLD,
-                // If no font is specified, it will use the default font.
-                ..default()
+            TextSection::from_style(if cfg!(feature = "default_font") {
+                TextStyle {
+                    font_size: 60.0,
+                    color: Color::GOLD,
+                    // If no font is specified, the default font (a minimal subset of FiraMono) will be used.
+                    ..default()
+                }
+            } else {
+                // "default_font" feature is unavailable, load a font to use instead.
+                TextStyle {
+                    font: asset_server.load("fonts/FiraMono-Medium.ttf"),
+                    font_size: 60.0,
+                    color: Color::GOLD,
+                }
             }),
         ]),
         FpsText,
     ));
+
+    #[cfg(feature = "default_font")]
+    commands.spawn(
+        // Here we are able to call the `From` method instead of creating a new `TextSection`.
+        // This will use the default font (a minimal subset of FiraMono) and apply the default styling.
+        TextBundle::from("From an &str into a TextBundle with the default font!").with_style(
+            Style {
+                position_type: PositionType::Absolute,
+                bottom: Val::Px(5.0),
+                left: Val::Px(15.0),
+                ..default()
+            },
+        ),
+    );
+
+    #[cfg(not(feature = "default_font"))]
+    commands.spawn(
+        TextBundle::from_section(
+            "Default font disabled",
+            TextStyle {
+                font: asset_server.load("fonts/FiraMono-Medium.ttf"),
+                ..default()
+            },
+        )
+        .with_style(Style {
+            position_type: PositionType::Absolute,
+            bottom: Val::Px(5.0),
+            left: Val::Px(15.0),
+            ..default()
+        }),
+    );
 }
 
 fn text_color_system(time: Res<Time>, mut query: Query<&mut Text, With<ColorText>>) {