Partially fix unicode name truncation.

This fix ensures that name truncation always happens on codepoint
boundaries and that a name has exactly 5 visible codepoints. This should
cover all possible cases unless names can have grapheme clusters, afaik
this is not the case.

src/types/unitframe.lua

@@ -53,6 +53,21 @@ local colors = {
     white = { 1.0, 1.0, 1.0 }
 }
 
+-- This trucates _codepoints_ not graphemes. If combination codepoints are
+-- contained in the string, it will not properly truncate and may return
+-- incorrect graphemes
+local function utf8_truncate(s, n)
+    local init = 0
+    for _ = 1, n do
+        local _, last = string.find(s, ".[\128-\191]*", init + 1)
+        if not last then
+            return s
+        end
+        init = last
+    end
+    return string.sub(s, 1, init)
+end
+
 ---@param unit string
 ---@param config table
 function UnitFrame:Init(unit, config)
@@ -585,20 +600,5 @@ function UnitFrame:UpdateName()
     else
         self.name:SetTextColor(1, 1, 1)
     end
-    self.name:SetText(UnitName(self.unit):sub(1, 5))
+    self.name:SetText(utf8_truncate((UnitName(self.unit)), 5))
 end
-
---[[
-    -- UNIT_AURA
-    -- UNIT_CLASSIFICATION_CHANGED
-    -- UNIT_COMBAT
-    -- UNIT_CONNECTION
-    -- UNIT_DISPLAYPOWER
-    -- UNIT_FACTION
-    -- UNIT_FLAGS
-    -- UNIT_LEVEL
-    -- UNIT_MANA
-    -- UNIT_HEALTH_PREDICTION
-    -- UNIT_PHASE
-]]--
-