Restore missing changelog comment
diff --git a/extensions/ARB/ARB_gl_spirv.txt b/extensions/ARB/ARB_gl_spirv.txt
index a7a4c9a..3931bd5 100644
--- a/extensions/ARB/ARB_gl_spirv.txt
+++ b/extensions/ARB/ARB_gl_spirv.txt
@@ -2122,6 +2122,8 @@
41 10-Dec-2018 Jon Leech Use 'workgroup' consistently
throughout (Bug 11723, internal API
issue 87).
+ 40 29-May-2018 dgkoch note post decrement for atomicCounterDecrement
+ mapping
39 25-Apr-2018 JohnK add mappings of barriers and atomics
38 10-Apr-2018 dgkoch OpImageQuerySizeLod and OpImageQuerylevels
only work with Sampled images