M3: translate the menu bar's own overflow sentinel to a glyph every font has

craft_menu writes "⋯" (U+22EF) itself for the menu of titles that don't fit, through the app's own label callback. No font this app ships or falls back to has that glyph, and egui 0.37's MissingGlyphPolicy::Panic crashes on it as soon as the bar is narrow enough to need it: every editing test that narrows the window while a paragraph is open hit this. The ordinary ellipsis the rest of the app already uses everywhere else is available and reads the same.

crates/ui-egui/src/menus.rs

@@ -256,9 +256,13 @@ fn english(labeled: Labeled<'_>) -> Option<String> {
 }
 
 fn translate(english: &'static str) -> String {
-    // The bundled UI fonts do not all cover the menu's mathematical ellipsis.
+    // craft_menu's bar writes "⋯" (U+22EF, MIDLINE HORIZONTAL ELLIPSIS) itself, for the menu of
+    // titles that don't fit: a sentinel to translate, not an English phrase, and the only one of
+    // its four reserved labels no font this app ships or falls back to has a glyph for.
+    // MissingGlyphPolicy::Panic (egui 0.37) crashes on it. The ordinary ellipsis every other
+    // truncated label in this app already uses is in the bundled faces.
     if english == "\u{22ef}" {
-        return "...".to_owned();
+        return "…".to_owned();
     }
     tl!(english).to_owned()
 }
@@ -662,6 +666,22 @@ mod tests {
         bar.find(command).unwrap_or_else(|| panic!("{} is in the menus", command.key()))
     }
 
+    /// The bar's own overflow-menu sentinel is not rendered as typed: no font this app ships or
+    /// falls back to has U+22EF, and egui 0.37's `MissingGlyphPolicy::Panic` crashes on it when
+    /// the menu bar is narrow enough to need it. The editing tests that narrow the window while a
+    /// paragraph is open reproduce this end to end. The other three reserved labels are plain
+    /// ASCII, so untranslated is safe for them.
+    #[test]
+    fn the_overflow_menu_sentinel_is_not_passed_through_untranslated() {
+        crate::i18n::set_current(crate::i18n::Lang::EN);
+        let translated = translate("⋯");
+        assert_ne!(translated, "⋯", "no installed font has this glyph");
+        assert_eq!(translated, "…", "the ordinary ellipsis the rest of the app already uses");
+        for label in ["Menu", "Scroll menu up", "Scroll menu down"] {
+            assert_eq!(translate(label), label, "plain ASCII reserved labels need no substitution");
+        }
+    }
+
     #[test]
     fn every_menu_command_is_listed_once_with_its_shortcut() {
         let (app, ctx) = app(&["a.pdf"]);