Fix comments with new font names and the used fallback

Author: vbfox

src/font/system.rs

@@ -133,9 +133,10 @@ impl fmt::Debug for FontSystem {
 ///
 /// * Use the system locale on `std` or `en-US` on `no_std`
 /// * Load system fonts
-/// * Use `Fira Mono` as the monospace family
-/// * Use `Fira Sans` as the sans-serif family
+/// * Use `Noto Sans Mono` as the monospace family
+/// * Use `Open Sans` as the sans-serif family
 /// * Use `DejaVu Serif` as the serif family
+/// * Use a platform-specific font fallback
 ///
 /// # Timing
 ///
@@ -300,11 +301,17 @@ impl FontSystemBuilder {
         self
     }
 
+    /// Sets the font fallback implementation
+    ///
+    /// Default: [PlatformFallback]
     pub fn dyn_fallback(mut self, fallback: Option<Box<dyn Fallback>>) -> Self {
         self.dyn_fallback = fallback;
         self
     }
 
+    /// Sets the font fallback implementation
+    ///
+    /// Default: [PlatformFallback]
     pub fn fallback(self, fallback: impl Fallback + 'static) -> Self {
         self.dyn_fallback(Some(Box::new(fallback)))
     }