LibJS+LibUnicode: Add "microsecond" and "nanosecond" as sanctioned units

This is a normative change in the ECMA-402 spec. See:
f627573

Meta/Lagom/Tools/CodeGenerators/LibLocale/GenerateNumberFormatData.cpp

@@ -638,10 +638,7 @@ static ErrorOr<void> parse_units(String locale_units_path, CLDR& cldr, LocaleDat
         // LibUnicode generally tries to avoid being directly dependent on ECMA-402, but this rather significantly reduces the amount
         // of data generated here, and ECMA-402 is currently the only consumer of this data.
         constexpr auto sanctioned_units = JS::Intl::sanctioned_single_unit_identifiers();
-        if (find(sanctioned_units.begin(), sanctioned_units.end(), unit_name) != sanctioned_units.end())
+        return find(sanctioned_units.begin(), sanctioned_units.end(), unit_name) != sanctioned_units.end();
-            return true;
-        static constexpr auto extra_sanctioned_units = JS::Intl::extra_sanctioned_single_unit_identifiers();
-        return find(extra_sanctioned_units.begin(), extra_sanctioned_units.end(), unit_name) != extra_sanctioned_units.end();
     };
 
     auto parse_units_object = [&](auto const& units_object, Locale::Style style) {

Userland/Libraries/LibJS/Runtime/Intl/SingleUnitIdentifiers.h

@@ -40,6 +40,7 @@ constexpr auto sanctioned_single_unit_identifiers()
         "megabit"sv,
         "megabyte"sv,
         "meter"sv,
+        "microsecond"sv,
         "mile"sv,
         "mile-scandinavian"sv,
         "milliliter"sv,
@@ -47,6 +48,7 @@ constexpr auto sanctioned_single_unit_identifiers()
         "millisecond"sv,
         "minute"sv,
         "month"sv,
+        "nanosecond"sv,
         "ounce"sv,
         "percent"sv,
         "petabyte"sv,
@@ -61,10 +63,4 @@ constexpr auto sanctioned_single_unit_identifiers()
     };
 }
 
-// Additional single units used in ECMAScript required by the Intl.DurationFormat proposal
-constexpr auto extra_sanctioned_single_unit_identifiers()
-{
-    return AK::Array { "microsecond"sv, "nanosecond"sv };
-}
-
 }

Userland/Libraries/LibJS/Tests/builtins/Intl/NumberFormat/NumberFormat.prototype.format.js

@@ -1518,6 +1518,15 @@ describe("style=unit", () => {
         expect(en2.format(1.2)).toBe("1.2 kilometers per hour");
         expect(en2.format(123)).toBe("123 kilometers per hour");
 
+        const en3 = new Intl.NumberFormat("en", {
+            style: "unit",
+            unit: "nanosecond",
+            unitDisplay: "long",
+        });
+        expect(en3.format(1)).toBe("1 nanosecond");
+        expect(en3.format(1.2)).toBe("1.2 nanoseconds");
+        expect(en3.format(123)).toBe("123 nanoseconds");
+
         const ar = new Intl.NumberFormat("ar", {
             style: "unit",
             unit: "foot",
@@ -1556,6 +1565,15 @@ describe("style=unit", () => {
         expect(en2.format(1.2)).toBe("1.2 km/h");
         expect(en2.format(123)).toBe("123 km/h");
 
+        const en3 = new Intl.NumberFormat("en", {
+            style: "unit",
+            unit: "nanosecond",
+            unitDisplay: "short",
+        });
+        expect(en3.format(1)).toBe("1 ns");
+        expect(en3.format(1.2)).toBe("1.2 ns");
+        expect(en3.format(123)).toBe("123 ns");
+
         const ar = new Intl.NumberFormat("ar", {
             style: "unit",
             unit: "foot",
@@ -1594,6 +1612,15 @@ describe("style=unit", () => {
         expect(en2.format(1.2)).toBe("1.2km/h");
         expect(en2.format(123)).toBe("123km/h");
 
+        const en3 = new Intl.NumberFormat("en", {
+            style: "unit",
+            unit: "nanosecond",
+            unitDisplay: "narrow",
+        });
+        expect(en3.format(1)).toBe("1ns");
+        expect(en3.format(1.2)).toBe("1.2ns");
+        expect(en3.format(123)).toBe("123ns");
+
         const ar = new Intl.NumberFormat("ar", {
             style: "unit",
             unit: "foot",