[gimp] devel-docs: update the icons doc with some of Mitch explanations.

[Jehan Pagès <jehanp src gnome org>]

commit 8493711f218c69cac1a459b305d911a52204dc2b
Author: Jehan <jehan girinstud io>
Date:   Sat Aug 6 02:16:09 2016 +0200

    devel-docs: update the icons doc with some of Mitch explanations.
    
    This explains a little better why some systems (i.e. GNOME…) would show
    no icons in menus whereas other (i.e. Linux Mint, Windows…) would show
    them. GIMP_ICONS_LIKE_A_BOSS environment variable is a developer trick
    to show icons in menus anyway to see how things render on such systems.

 devel-docs/icons.txt |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/devel-docs/icons.txt b/devel-docs/icons.txt
index 75b1b38..8f69ad3 100644
--- a/devel-docs/icons.txt
+++ b/devel-docs/icons.txt
@@ -104,9 +104,10 @@ Some known sizes:
 Testing icons
 -------------
 
-Icons in menus are not always shown. In particular some desktop environments
-would not show them by default, for instance GNOME. You can force them to
-show up by setting the environment variable `GIMP_ICONS_LIKE_A_BOSS`.
+Menu items and buttons are not supposed to have icons any longer. Yet
+our actions have icons and some desktop environments would enable them
+in menus and buttons regardless. To test how we do on systems which do
+so, set the environment variable `GIMP_ICONS_LIKE_A_BOSS`.
 
 For instance, start GIMP like this: