Fix docs typo

Co-authored-by: Dale Wijnand <[email protected]>

Author: OlivierBlanvillain

compiler/src/dotty/tools/dotc/core/TypeComparer.scala

@@ -2564,7 +2564,7 @@ class TypeComparer(@constructorOnly initctx: Context) extends ConstraintHandling
             // of classes.
             true
           else if (isDecomposable(cls1))
-            // At this point, !cls1.derivesFrom(cls2): we know that `new cls2`
+            // At this point, !cls1.derivesFrom(cls2): we know that `cls1`
             // is disjoint from `tp2`. Therefore, we can safely decompose
             // `cls1` using `.children`, even if `cls1` is non abstract.
             decompose(cls1, tp1).forall(x => provablyDisjoint(x, tp2))