fix: for consistency, implement CalcSunrise in terms of CalcDawn.

Signed-off-by: Jon Seymour <[email protected]>

astrotime.go

@@ -335,10 +335,7 @@ func CalcDawn(t time.Time, latitude float64, longitude float64, solarElevation f
 // CalcSunrise calculates the sunrise, in local time,  on the day t at the
 // location specified in longitude and latitude.
 func CalcSunrise(t time.Time, latitude float64, longitude float64) time.Time {
-	jd := CalcJD(t)
-	sunriseUTC := time.Duration(math.Floor(calcSunriseUTC(jd, latitude, longitude, SUNRISE)*60) * 1e9)
-	loc, _ := time.LoadLocation("UTC")
-	return time.Date(t.Year(), t.Month(), t.Day(), 0, 0, 0, 0, loc).Add(sunriseUTC).In(t.Location())
+	return CalcDawn(t, latitude, longitude, SUNRISE)
 }
 
 // Calculates the refractive correction for the specified solar elevation.