FormattedDateRange

Renders start–end as a single date when they fall on the same day, and collapses shared year/month for fi/sv (e.g. "1.–3.5.2026"). Any other locale (eg. en) gets no collapsing, and its two endpoints are separated by non-breaking spaces around the dash so it doesn't get lost among the date's own hyphens.

• Same day, locale="fi": 5.8.2026
• Same month & year, locale="fi": 1.–3.8.2026
• Same month & year, locale="sv" (identical to fi): 1.–3.8.2026
• Same year, different months, locale="fi": 28.4.–3.5.2026
• Different years, locale="fi": 30.12.2026–2.1.2027
• Same month & year as above, locale="en" (no collapsing): 2026-08-01 – 2026-08-03
• Only start given, locale="fi": 5.8.2026
• Only end given, locale="fi": 5.8.2026