Update 6-garbage-collector-perf.adoc

blog/modules/ROOT/pages/6-garbage-collector-perf.adoc

@@ -427,7 +427,7 @@ _Garbage Collection_ and _Reference Counting_ have very different characteristic
 is strictly superior to the other in all scenarios.
 Many programming languages (e.g. Python) that use reference counting also have a backup
 tracing garbage collector that runs once in a while to clean up unreachable reference cycles
-and compact the heap, and most modern GCs (e.g. ZGC discussed above) use some reference-counting
+and compact the heap, and most modern GCs (e.g. ZGC discussed below) use some reference-counting
 techniques as part of their implementation.
 
 
@@ -802,4 +802,4 @@ for language users to tweak and tune.
 However, at a high level most GCs are actually surprisingly similar, have the same
 odd performance characteristics, and the same surprising pitfalls.
 Hopefully this article will have given you a good intuition for how garbage collectors work and behave, so
-next time you need to do something with your GC you have a solid understanding to work with.
+next time you need to do something with your GC you have a solid understanding to work with.