wezterm-font: bundle a last resort font

Bundle the *Last Resort High-Efficiency* font from
https://github.com/unicode-org/last-resort-font/
version 13.001 (Oct 22 2020).

This provides a more useful fallback glyph than we'd otherwise
produce if there is no matching glyph in any of the fonts.

Its license is OFL-1.1 which is compatible with the other
bundled fonts.

config/src/font.rs

@@ -172,6 +172,9 @@ impl TextStyle {
         // We bundle this emoji font as an in-memory fallback
         font.push(FontAttributes::new_fallback("Noto Color Emoji"));
 
+        // And finally, a last resort fallback font
+        font.push(FontAttributes::new_fallback("Last Resort High-Efficiency"));
+
         font
     }
 }

wezterm-font/src/parser.rs

@@ -600,6 +600,7 @@ fn load_built_in_fonts(
         font!("../../assets/fonts/JetBrainsMono-SemiLight-Italic.ttf"),
         font!("../../assets/fonts/JetBrainsMono-SemiLight.ttf"),
         font!("../../assets/fonts/NotoColorEmoji.ttf"),
+        font!("../../assets/fonts/LastResortHE-Regular.ttf"),
     ] {
         let scope = allsorts::binary::read::ReadScope::new(&data);
         let file = scope.read::<OpenTypeFile>()?;