Resolve the "ft" unit suffix to Feet in Unit::named

Found while testing crates/doc/src/lib.rs:274 (Unit::named)

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

crates/doc/src/lib.rs

@@ -274,7 +274,12 @@ impl Unit {
     pub fn named(name: &str) -> Option<Unit> {
         let letters = |s: &'static str| s.chars().filter(char::is_ascii_alphanumeric).map(|c| c.to_ascii_lowercase());
         let given = || name.chars().filter(char::is_ascii_alphanumeric).map(|c| c.to_ascii_lowercase());
-        Unit::ALL.into_iter().find(|u| letters(u.label()).eq(given()) || u.suffix().chars().eq(given()))
+        // Feet and Feet & Inches share the suffix `ft`: it names the plain unit, so Feet & Inches
+        // is left to its label and key.
+        Unit::ALL
+            .into_iter()
+            .find(|u| letters(u.label()).eq(given()))
+            .or_else(|| Unit::ALL.into_iter().filter(|u| *u != Unit::FeetInches).find(|u| u.suffix().chars().eq(given())))
     }
     /// A point value as the canvas measurement labels show it: two decimals and the suffix
     /// (`12.50 mm`).

crates/doc/src/tests_units.rs

@@ -98,6 +98,13 @@ fn units_are_named_by_label_key_or_suffix() {
     assert_eq!(Unit::named(""), None);
 }
 
+#[test]
+fn a_shared_suffix_names_the_plain_unit() {
+    assert_eq!(Unit::named(Unit::Feet.suffix()), Some(Unit::Feet));
+    assert_eq!(Unit::named("FT"), Some(Unit::Feet));
+    assert_eq!(Unit::named(Unit::FeetInches.label()), Some(Unit::FeetInches));
+}
+
 #[test]
 fn readouts_show_two_decimals() {
     assert_eq!(Unit::Points.readout(15.0), "15.00 pt");