Fix Catppuccin diff viewer - restore distinct colors for each diff type

Fixed the issue where removed lines weren't showing in red. Now using:
- Added lines: color120 (bright green text) on color232 (near-black)
- Removed lines: color210 (bright red/pink text) on color232
- Changed lines: color117 (bright cyan text) on color232
- Changed new: color210 (bright red/pink) on color232

All text colors are bright and distinct while backgrounds remain
consistently dark (color232) for maximum contrast. Each diff type
is now clearly distinguishable:
- Green = additions
- Red/Pink = deletions
- Cyan = changes

Author: rafaelvzago

misc/skins/catppuccin256.ini

@@ -124,12 +124,12 @@
     viewselected = color228;color189
 
 [diffviewer]
-    changedline = color231;color232
+    changedline = color117;color232
     changednew = color210;color232
-    changed = color189;color232
-    added = color151;color232
+    changed = color117;color232
+    added = color120;color232
     removed = color210;color232
-    error = color210;color233
+    error = color231;color52
 
 [widget-panel]
     sort-up-char = ↑