[gimp] data: improve the tip about the save and export format.

[Jehan Pagès <jehanp src gnome org>]

commit 127b8470f994d9709a9f42f809c88ba6f7bb3394
Author: Jehan <jehan girinstud io>
Date:   Tue Feb 13 00:54:53 2018 +0100

    data: improve the tip about the save and export format.
    
    Current phrasing seemed to imply that you could chose another format
    than XCF to *save* your work-in-progress image. Reword a bit to make
    obvious that "saving" is always done with XCF. Other formats are for
    exporting.

 data/tips/gimp-tips.xml.in |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/data/tips/gimp-tips.xml.in b/data/tips/gimp-tips.xml.in
index 38de9b7..61e66f2 100644
--- a/data/tips/gimp-tips.xml.in
+++ b/data/tips/gimp-tips.xml.in
@@ -35,9 +35,9 @@
   </tip>
   <tip level="beginner" help="gimp-file-save">
     <_thetip>
-      When you save an image to work on it again later, try using XCF,
-      GIMP's native file format (use the file extension <tt>.xcf</tt>).
-      This preserves the layers and many aspects of your work-in-progress.
+      Saving an image uses XCF, GIMP's native file format (file extension
+      <tt>.xcf</tt>). This preserves the layers and many aspects of your
+      work-in-progress, allowing to work on it again later.
       Once a project is completed, you can export it as JPEG, PNG, GIF, etc.
     </_thetip>
   </tip>