Assume Moon's equatorial coordinates are geocentric

During my researches, I discover that equatorial coordinates don't
necessarily have to be geocentric. Thinking I would have to make the
difference in the Moon's public API, I created
`Moon#apparent_geocentric_equatorial_coordinates`.

After some more work, I understood only the geocentric parallax was
necessary to apply to have topocentric coordinates. Because they are
only necessary for topocentric coordinates, such as horizontal
coordinates, and for consistent method names, this change renames
`Moon#apparent_geocentric_equatorial_coordinates` into
`Moon#aparent_equatorial_coordinates`.

No behaviour change was introduced.

lib/astronoby/bodies/moon.rb

@@ -37,11 +37,10 @@ def apparent_ecliptic_coordinates
 
     # @return [Astronoby::Coordinates::Equatorial] Apparent geocentric
     #   equatorial coordinates of the Moon
-    def apparent_geocentric_equatorial_coordinates
-      @apparent_geocentric_equatorial_coordinates ||= begin
-        ecliptic = apparent_ecliptic_coordinates
-        ecliptic.to_apparent_equatorial(epoch: Epoch.from_time(@time))
-      end
+    def apparent_equatorial_coordinates
+      @apparent_equatorial_coordinates ||=
+        apparent_ecliptic_coordinates
+          .to_apparent_equatorial(epoch: Epoch.from_time(@time))
     end
 
     def horizontal_coordinates(observer:)
@@ -51,7 +50,7 @@ def horizontal_coordinates(observer:)
           longitude: observer.longitude,
           elevation: observer.elevation,
           time: @time,
-          coordinates: apparent_geocentric_equatorial_coordinates,
+          coordinates: apparent_equatorial_coordinates,
           distance: distance
         )
 

spec/astronoby/bodies/moon_spec.rb

@@ -121,7 +121,7 @@
     end
   end
 
-  describe "#apparent_geocentric_equatorial_coordinates" do
+  describe "#apparent_equatorial_coordinates" do
     # Source:
     #  Title: Astronomical Algorithms
     #  Author: Jean Meeus
@@ -133,7 +133,7 @@
       time -= Astronoby::Util::Time.terrestrial_universal_time_delta(time)
       moon = described_class.new(time: time)
 
-      coordinates = moon.apparent_geocentric_equatorial_coordinates
+      coordinates = moon.apparent_equatorial_coordinates
 
       expect(coordinates.right_ascension.str(:hms)).to eq "8h 58m 45.21s"
       # Result from the book: 8h 58m 45.1s
@@ -152,7 +152,7 @@
     it "returns the apparent geocentric equatorial coordinates for 2015-01-01" do
       moon = described_class.new(time: Time.new(2015, 1, 1, 22, 0, 0, "-05:00"))
 
-      coordinates = moon.apparent_geocentric_equatorial_coordinates
+      coordinates = moon.apparent_equatorial_coordinates
 
       expect(coordinates.right_ascension.str(:hms)).to eq "4h 16m 35.1442s"
       # Result from the book: 4h 15m 27.7703s (4.257714h)
@@ -171,7 +171,7 @@
     it "returns the apparent geocentric equatorial coordinates for 2000-08-09" do
       moon = described_class.new(time: Time.new(2000, 8, 9, 12, 0, 0, "-05:00"))
 
-      coordinates = moon.apparent_geocentric_equatorial_coordinates
+      coordinates = moon.apparent_equatorial_coordinates
 
       expect(coordinates.right_ascension.str(:hms)).to eq "17h 6m 3.1276s"
       # Result from the book: 17h 5m 41.2872s (17.094802h)
@@ -190,7 +190,7 @@
     it "returns the apparent geocentric equatorial coordinates for 2010-05-15" do
       moon = described_class.new(time: Time.new(2010, 5, 15, 14, 30, 0, "-04:00"))
 
-      coordinates = moon.apparent_geocentric_equatorial_coordinates
+      coordinates = moon.apparent_equatorial_coordinates
 
       expect(coordinates.right_ascension.str(:hms)).to eq "5h 0m 44.3733s"
       # Result from the book: 4h 59m 54.1103s (4.998364h)
@@ -209,7 +209,7 @@
     it "returns the apparent geocentric equatorial coordinates for 2003-09-01" do
       moon = described_class.new(time: Time.utc(2003, 9, 1))
 
-      coordinates = moon.apparent_geocentric_equatorial_coordinates
+      coordinates = moon.apparent_equatorial_coordinates
 
       expect(coordinates.right_ascension.str(:hms)).to eq "14h 12m 12.2352s"
       # Result from the book: 14h 12m 42s