And revert the comment, too

src/compiler/checker.ts

@@ -13485,7 +13485,7 @@ namespace ts {
         // Return true if the given type is deeply nested. We consider this to be the case when structural type comparisons
         // for 5 or more occurrences or instantiations of the type have been recorded on the given stack. It is possible,
         // though highly unlikely, for this test to be true in a situation where a chain of instantiations is not infinitely
-        // expanding. Effectively, we will generate a false positive when two types are structurally equal to at least 4
+        // expanding. Effectively, we will generate a false positive when two types are structurally equal to at least 5
         // levels, but unequal at some level beyond that.
         function isDeeplyNestedType(type: Type, stack: Type[], depth: number): boolean {
             // We track all object types that have an associated symbol (representing the origin of the type)