fix(i18n): name the period in the forecast style hints

Only the selected style's hint is shown, so "it may start" and "they
may fall" had no noun on screen to point back to. Name the period in
every locale that left it implied, and put the Korean hints in the same
register as the rest of the card.

src/components/cycle/__tests__/cycle-calendar-feed-card.test.tsx

@@ -71,7 +71,7 @@ describe("<CycleCalendarFeedCard>", () => {
     }
     expect(html).toContain('aria-describedby="cycle-feed-forecast-hint"');
     expect(html).toMatch(
-      /data-slot="cycle-feed-forecast-hint"[^>]*>Expected days, with the days it may start earlier or later as separate entries\.</,
+      /data-slot="cycle-feed-forecast-hint"[^>]*>Expected days, with the days the period may start earlier or later as separate entries\.</,
     );
 
     const band = render({
@@ -79,7 +79,9 @@ describe("<CycleCalendarFeedCard>", () => {
       projectionState: "OK",
       fertileAvailable: false,
     });
-    expect(band).toContain("One entry covering every day it may fall on.");
+    expect(band).toContain(
+      "One entry covering every day the period may fall on.",
+    );
     expect(band).not.toContain("as separate entries");
   });