[gimp-web] Fix again development release Linux/flatpak info.

[Jehan <jehanp src gnome org>]

commit fe0dfc75a6b68cc4e8204a65bcbf6fe50d7cf7f5
Author: Jehan <jehan girinstud io>
Date:   Sun Nov 8 16:24:58 2020 +0100

    Fix again development release Linux/flatpak info.
    
    Actually we can install in one command with the flatpakref (which
    contains runtime information).
    
    Also use <pre/><code/> instead of <code/><pre/>

 themes/newgimp/templates/downloads-development.html | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)
---
diff --git a/themes/newgimp/templates/downloads-development.html 
b/themes/newgimp/templates/downloads-development.html
index d1dbb158..3e716182 100644
--- a/themes/newgimp/templates/downloads-development.html
+++ b/themes/newgimp/templates/downloads-development.html
@@ -78,13 +78,10 @@
         <h3>Flatpak additional instructions</h3>
 
         <p>If the link above doesn't open your software installer,
-        install with following command lines:
+        install with following command:
         <p>
-        <code><pre>
-          flatpak remote-add --user flathub-beta https://flathub.org/beta-repo/flathub-beta.flatpakrepo
-          flatpak remote-add --user flathub https://dl.flathub.org/repo/flathub.flatpakrepo
-          flatpak install --user flathub-beta org.gimp.GIMP
-        </pre></code>
+        <code>
+          flatpak install --user https://flathub.org/beta-repo/appstream/org.gimp.GIMP.flatpakref
         </code>
         </p>
         <p>
@@ -108,10 +105,10 @@
         version:</em>
         </p>
         <p>
-        <code><pre>
+        <pre><code>
           flatpak make-current --user org.gimp.GIMP stable
           flatpak make-current --user org.gimp.GIMP beta
-        </pre></code>
+        </code></pre>
         </p>
         <p>
         <em>You may also create shortcuts running these specific