docs: 统一公开 API 的中英双语注释

- 补齐公开接口说明段的英文描述，保持签名注释和详细说明均为中英双语结构
- 规范农历、坐标、公式、轨道、日晷、太阳、恒星及行星事件等 API 的注释口径

saturn/saturn.go

@@ -208,6 +208,7 @@ func SetTime(date time.Time, lon, lat, height float64, aero bool) (time.Time, er
 // LastConjunction 上一次合日 / previous conjunction with the Sun.
 //
 // 返回 date 当前或之前最近一次与太阳的合日时刻，结果保持 date 的时区。
+// Returns the nearest conjunction with the Sun at or before date, keeping date's time zone.
 func LastConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastSaturnConjunction(jde), date.Location(), false)
@@ -216,6 +217,7 @@ func LastConjunction(date time.Time) time.Time {
 // NextConjunction 下一次合日 / next conjunction with the Sun.
 //
 // 返回 date 当前或之后最近一次与太阳的合日时刻，结果保持 date 的时区。
+// Returns the nearest conjunction with the Sun at or after date, keeping date's time zone.
 func NextConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextSaturnConjunction(jde), date.Location(), false)
@@ -224,6 +226,7 @@ func NextConjunction(date time.Time) time.Time {
 // LastOpposition 上一次冲日 / previous opposition.
 //
 // 返回 date 当前或之前最近一次冲日时刻，结果保持 date 的时区。
+// Returns the nearest opposition at or before date, keeping date's time zone.
 func LastOpposition(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastSaturnOpposition(jde), date.Location(), false)
@@ -232,6 +235,7 @@ func LastOpposition(date time.Time) time.Time {
 // NextOpposition 下一次冲日 / next opposition.
 //
 // 返回 date 当前或之后最近一次冲日时刻，结果保持 date 的时区。
+// Returns the nearest opposition at or after date, keeping date's time zone.
 func NextOpposition(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextSaturnOpposition(jde), date.Location(), false)
@@ -240,6 +244,7 @@ func NextOpposition(date time.Time) time.Time {
 // LastProgradeToRetrograde 上一次顺行转逆行留 / previous station from prograde to retrograde.
 //
 // 返回 date 当前或之前最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
+// Returns the nearest station at or before date where motion changes from prograde to retrograde, keeping date's time zone.
 func LastProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastSaturnProgradeToRetrograde(jde), date.Location(), false)
@@ -248,6 +253,7 @@ func LastProgradeToRetrograde(date time.Time) time.Time {
 // NextProgradeToRetrograde 下一次顺行转逆行留 / next station from prograde to retrograde.
 //
 // 返回 date 当前或之后最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
+// Returns the nearest station at or after date where motion changes from prograde to retrograde, keeping date's time zone.
 func NextProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextSaturnProgradeToRetrograde(jde), date.Location(), false)
@@ -256,6 +262,7 @@ func NextProgradeToRetrograde(date time.Time) time.Time {
 // LastRetrogradeToPrograde 上一次逆行转顺行留 / previous station from retrograde to prograde.
 //
 // 返回 date 当前或之前最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
+// Returns the nearest station at or before date where motion changes from retrograde to prograde, keeping date's time zone.
 func LastRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastSaturnRetrogradeToPrograde(jde), date.Location(), false)
@@ -264,6 +271,7 @@ func LastRetrogradeToPrograde(date time.Time) time.Time {
 // NextRetrogradeToPrograde 下一次逆行转顺行留 / next station from retrograde to prograde.
 //
 // 返回 date 当前或之后最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
+// Returns the nearest station at or after date where motion changes from retrograde to prograde, keeping date's time zone.
 func NextRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextSaturnRetrogradeToPrograde(jde), date.Location(), false)
@@ -272,6 +280,7 @@ func NextRetrogradeToPrograde(date time.Time) time.Time {
 // LastEasternQuadrature 上一次东方照 / previous eastern quadrature.
 //
 // 返回 date 当前或之前最近一次东方照时刻，结果保持 date 的时区。
+// Returns the nearest eastern quadrature at or before date, keeping date's time zone.
 func LastEasternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastSaturnEasternQuadrature(jde), date.Location(), false)
@@ -280,6 +289,7 @@ func LastEasternQuadrature(date time.Time) time.Time {
 // NextEasternQuadrature 下一次东方照 / next eastern quadrature.
 //
 // 返回 date 当前或之后最近一次东方照时刻，结果保持 date 的时区。
+// Returns the nearest eastern quadrature at or after date, keeping date's time zone.
 func NextEasternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextSaturnEasternQuadrature(jde), date.Location(), false)
@@ -288,6 +298,7 @@ func NextEasternQuadrature(date time.Time) time.Time {
 // LastWesternQuadrature 上一次西方照 / previous western quadrature.
 //
 // 返回 date 当前或之前最近一次西方照时刻，结果保持 date 的时区。
+// Returns the nearest western quadrature at or before date, keeping date's time zone.
 func LastWesternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastSaturnWesternQuadrature(jde), date.Location(), false)
@@ -296,6 +307,7 @@ func LastWesternQuadrature(date time.Time) time.Time {
 // NextWesternQuadrature 下一次西方照 / next western quadrature.
 //
 // 返回 date 当前或之后最近一次西方照时刻，结果保持 date 的时区。
+// Returns the nearest western quadrature at or after date, keeping date's time zone.
 func NextWesternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextSaturnWesternQuadrature(jde), date.Location(), false)