[gegl] bilateral-filter-fast: add more explaination for its workshop exile

[Øyvind Kolås <ok src gnome org>]

commit 47b2ad3c7e347eacb275f8e82dc87d9a814b1249
Author: Øyvind Kolås <pippin gimp org>
Date:   Sat Apr 29 15:48:42 2017 +0200

    bilateral-filter-fast: add more explaination for its workshop exile

 operations/workshop/bilateral-filter-fast.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/operations/workshop/bilateral-filter-fast.c b/operations/workshop/bilateral-filter-fast.c
index 3354155..c57c292 100644
--- a/operations/workshop/bilateral-filter-fast.c
+++ b/operations/workshop/bilateral-filter-fast.c
@@ -1,4 +1,6 @@
-/* XXX: moved to workshop due to bug #777699, excessive memory allocations
+/* XXX: moved to workshop due to bug #777699, excessive memory allocations -
+ *      the op is not a crucial image processing tool - and can possibly even
+ *      be fully removed.
  */