Use preferred chars among duplicates as per UTR#25 §25.

lisp/international/iso-transl.el

@@ -182,10 +182,10 @@
     ("o"    . [?°])
     ("Oe"   . [?œ])
     ("OE"   . [?Œ])
-    ("*u"   . [?µ])
-    ("u"    . [?µ])
-    ("*m"   . [?µ])
-    ("m"    . [?µ])
+    ("*u"   . [?μ])
+    ("u"    . [?μ])
+    ("*m"   . [?μ])
+    ("m"    . [?μ])
     ("*x"   . [?×])
     ("x"    . [?×])
     ("*|"   . [?¦])

lisp/leim/quail/compose.el

@@ -464,9 +464,9 @@ Examples:
  ("2^" ?²)
  ("^3" ?³)
  ("3^" ?³)
- ("mu" ?µ)
- ("/u" ?µ)
- ("u/" ?µ)
+ ("mu" ?μ)
+ ("/u" ?μ)
+ ("u/" ?μ)
  ("^1" ?¹)
  ("1^" ?¹)
  ("^_o" ?º)

lisp/leim/quail/symbol-ksc.el

@@ -39,7 +39,7 @@
  "한글심벌입력표:
   【(】괄호열기【arrow】화살【sex】♂♀【index】첨자  【accent】악센트
   【)】괄호닫기【music】음악【dot】점  【quote】따옴표【xtext】§※¶¡¿
-  【Unit】℃Å￠℉【math】수학기호【pic】상형문자【line】선문자
+  【Unit】℃Å￠℉【math】수학기호【pic】상형문자【line】선문자
   【unit】단위    【frac】분수    【textline】­―∥＼∼
   【wn】㈜【ks】㉿【No】№【㏇】㏇ 【dag】† 【ddag】‡【percent】‰
   【am】㏂【pm】㏘【™】™【Tel】℡【won】￦ 【yen】￥ 【pound】￡
@@ -65,7 +65,7 @@
  ("dot"	"·‥…¨ː")
  ("quote"	"、。〃‘’“”°′″´˝")
  ("textline"	"­―∥＼∼")
- ("Unit"	"℃Å￠℉")
+ ("Unit"	"℃Å￠℉")
  ("sex"	"♂♀")
  ("accent"	"～ˇ˘˚˙¸˛")
  ("percent"	"‰")