LibJS: Use numeric style if the previous style was numeric or 2-digit

This is a normative change in the Intl.DurationFormat proposal. See:
3a46ee3

Userland/Libraries/LibJS/Runtime/Intl/DurationFormat.cpp

@@ -252,7 +252,12 @@ ThrowCompletionOr<DurationUnitOptions> get_duration_unit_options(VM& vm, String
             // i. Set style to digitalBase.
             style = digital_base;
         }
-        // c. Else,
+        // c. Else if prevStyle is "numeric" or "2-digit", then
+        else if (previous_style == "numeric"sv || previous_style == "2-digit"sv) {
+            // i. Set style to "numeric".
+            style = "numeric"sv;
+        }
+        // d. Else,
         else {
             // i. Set style to baseStyle.
             style = base_style;

Userland/Libraries/LibJS/Tests/builtins/Intl/DurationFormat/DurationFormat.js

@@ -266,6 +266,10 @@ describe("normal behavior", () => {
             }).not.toThrow();
         });
         ["numeric", "2-digit"].forEach(seconds => {
+            expect(() => {
+                new Intl.DurationFormat("en", { hours: seconds });
+            }).not.toThrow();
+
             expect(() => {
                 new Intl.DurationFormat("en", { style: "digital", hours: seconds });
             }).not.toThrow();
@@ -287,6 +291,10 @@ describe("normal behavior", () => {
             }).not.toThrow();
         });
         ["numeric", "2-digit"].forEach(seconds => {
+            expect(() => {
+                new Intl.DurationFormat("en", { minutes: seconds });
+            }).not.toThrow();
+
             expect(() => {
                 new Intl.DurationFormat("en", { style: "digital", minutes: seconds });
             }).not.toThrow();
@@ -308,6 +316,10 @@ describe("normal behavior", () => {
             }).not.toThrow();
         });
         ["numeric", "2-digit"].forEach(seconds => {
+            expect(() => {
+                new Intl.DurationFormat("en", { seconds: seconds });
+            }).not.toThrow();
+
             expect(() => {
                 new Intl.DurationFormat("en", { style: "digital", seconds: seconds });
             }).not.toThrow();
@@ -328,6 +340,11 @@ describe("normal behavior", () => {
                 new Intl.DurationFormat("en", { milliseconds: milliseconds });
             }).not.toThrow();
         });
+
+        expect(() => {
+            new Intl.DurationFormat("en", { milliseconds: "numeric" });
+        }).not.toThrow();
+
         expect(() => {
             new Intl.DurationFormat("en", { style: "digital", milliseconds: "numeric" });
         }).not.toThrow();
@@ -347,6 +364,11 @@ describe("normal behavior", () => {
                 new Intl.DurationFormat("en", { microseconds: microseconds });
             }).not.toThrow();
         });
+
+        expect(() => {
+            new Intl.DurationFormat("en", { microseconds: "numeric" });
+        }).not.toThrow();
+
         expect(() => {
             new Intl.DurationFormat("en", { style: "digital", microseconds: "numeric" });
         }).not.toThrow();
@@ -366,6 +388,11 @@ describe("normal behavior", () => {
                 new Intl.DurationFormat("en", { nanoseconds: nanoseconds });
             }).not.toThrow();
         });
+
+        expect(() => {
+            new Intl.DurationFormat("en", { nanoseconds: "numeric" });
+        }).not.toThrow();
+
         expect(() => {
             new Intl.DurationFormat("en", { style: "digital", nanoseconds: "numeric" });
         }).not.toThrow();