fix: simplify emoji color check algorithm (#139)

* fix: simplify emoji color check algorithm

* fix: clarify code comment

bin/versionsAndTestEmoji.js

@@ -1,5 +1,12 @@
-// Find one good representative emoji to test. Ideally it should have color in the center.
-// For some inspiration, see: https://about.gitlab.com/blog/2018/05/30/journey-in-native-unicode-emoji/
+// Find one good representative emoji from each version to test by checking its color.
+// Ideally it should have color in the center. For some inspiration, see:
+// https://about.gitlab.com/blog/2018/05/30/journey-in-native-unicode-emoji/
+//
+// Note that for certain versions (12.1, 13.1), there is no point in testing them explicitly, because
+// all the emoji from this version are compound-emoji from previous versions. So they would pass a color
+// test, even in browsers that display them as double emoji. (E.g. "face in clouds" might render as
+// "face without mouth" plus "fog".) These emoji can only be filtered using the width test,
+// which happens in checkZwjSupport.js.
 export const versionsAndTestEmoji = {
   '😃': 0.6,
   '😐️': 0.7,
@@ -9,8 +16,6 @@ export const versionsAndTestEmoji = {
   '👱‍♀️': 4,
   '🤩': 5,
   '🥰': 11, // smiling face with hearts
-  '🥻': 12, // sari
-  '🧑‍🦰': 12.1, // person: red hair
-  '🥲': 13, // smiling face with tear
-  '😵‍💫': 13.1 // face with spiral eyes
+  '🥻': 12.1, // sari, technically from v12 but see note above
+  '🥲': 13.1 // smiling face with tear, technically from v13 but see note above
 }