[gimp-web/testing] Add a paragraph about the improved memory management in GEGL.

[Jehan <jehanp src gnome org>]

commit d8565763c2b3b2e7378ff625c9c53b4bab81bcd0
Author: Jehan <jehan girinstud io>
Date:   Wed Jun 12 22:00:07 2019 +0200

    Add a paragraph about the improved memory management in GEGL.
    
    GEGL now helps the underlying libc by releasing memory manually with
    malloc_trim() sometimes.

 content/news/2019-06_GIMP-2.10.12_Released/index.md | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/content/news/2019-06_GIMP-2.10.12_Released/index.md 
b/content/news/2019-06_GIMP-2.10.12_Released/index.md
index fccbd270..e80e3b63 100644
--- a/content/news/2019-06_GIMP-2.10.12_Released/index.md
+++ b/content/news/2019-06_GIMP-2.10.12_Released/index.md
@@ -253,6 +253,14 @@ cases. Now in all places where there is choice of interpolation (all
 transformation tools, *Warp Transform* tool, etc.), the result with *cubic*
 has changed and produces sharper results.
 
+Another notable improvement in GEGL is an updated memory management, by
+conditionally freeing memory from the heap (thanks to manual calls of
+`malloc_trim()`), hence forcing the underlying `libc` to release memory
+more often. This behavior is especially suitable for long-running
+applications whose memory need can greatly vary, such as GIMP.
+In practice, it means that GIMP process' memory size will now shrink
+much faster when you will close big images on supporting systems.
+
 # What's next
 
 Though it gets less visibility, work on upcoming GIMP 3 continues and is