Unit frames: anchor the heal prediction to the health fill's edge

ClassicAPI v1.19.1 moves a status bar texture's rect with the fill, so
the prediction starts at GetStatusBarTexture() and is only as wide as the
incoming heal. It follows the health bar while it animates instead of
sitting at the final value.

api/unitframes.lua

@@ -853,12 +853,16 @@ function pfUI.uf:UpdateConfig()
   f.incHeal.texture:SetVertexColor(cr, cg, cb, ca)
   f.incHeal:Hide()
 
-  if f.config.verticalbar == "0" then
-    f.incHeal:ClearAllPoints()
-    f.incHeal:SetPoint("TOPLEFT", f.hp.bar, "TOPLEFT", 0, 0)
+  -- the bar texture covers only the fill, so a prediction anchored to it
+  -- starts at the edge of the health and follows it as the bar animates.
+  -- An inverted bar fills with the missing health, so it starts at the bar.
+  f.incHeal:ClearAllPoints()
+  if f.config.invert_healthbar == "1" then
+    f.incHeal:SetPoint(f.config.verticalbar == "0" and "TOPLEFT" or "BOTTOM", f.hp.bar)
+  elseif f.config.verticalbar == "0" then
+    f.incHeal:SetPoint("TOPLEFT", f.hp.bar:GetStatusBarTexture(), "TOPRIGHT")
   else
-    f.incHeal:ClearAllPoints()
-    f.incHeal:SetPoint("BOTTOM", f.hp.bar, "BOTTOM", 0, 0)
+    f.incHeal:SetPoint("BOTTOMLEFT", f.hp.bar:GetStatusBarTexture(), "TOPLEFT")
   end
 
   f.ressIcon:SetFrameLevel(16)
@@ -1259,24 +1263,14 @@ function pfUI.uf.OnUpdate()
               if healthWidth + incWidth > width * (1+(overhealperc/100)) then
                 incWidth = width * (1+overhealperc/100) - healthWidth
               end
-
-              if this.config.invert_healthbar == "1" then
-                this.incHeal:SetWidth(incWidth)
-              else
-                this.incHeal:SetWidth(incWidth + healthWidth)
-              end
+              this.incHeal:SetWidth(incWidth)
             else
               local healthHeight = height * (health / maxHealth)
               local incHeight = height * heal / maxHealth
               if healthHeight + incHeight > height * (1+(overhealperc/100)) then
                 incHeight = height * (1+overhealperc/100) - healthHeight
               end
-
-              if this.config.invert_healthbar == "1" then
-                this.incHeal:SetHeight(incHeight)
-              else
-                this.incHeal:SetHeight(incHeight + healthHeight)
-              end
+              this.incHeal:SetHeight(incHeight)
             end
 
             this.incHeal:Show()