[geary/mjog/558-webkit-shared-process] Add release note about conversation loading perf

[Michael Gratton <mjog src gnome org>]

commit 9eff8a36f063ba07fc0ce34f45f39ea5d0d8776f
Author: Michael Gratton <mike vee net>
Date:   Wed Nov 27 10:37:49 2019 +1100

    Add release note about conversation loading perf

 desktop/org.gnome.Geary.appdata.xml.in.in | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/desktop/org.gnome.Geary.appdata.xml.in.in b/desktop/org.gnome.Geary.appdata.xml.in.in
index 108db1d9..86dc9491 100644
--- a/desktop/org.gnome.Geary.appdata.xml.in.in
+++ b/desktop/org.gnome.Geary.appdata.xml.in.in
@@ -101,6 +101,7 @@
           <li>Extend undo for email actions such as archiving, marking</li>
           <li>Undo sending, saving and discarding composed email</li>
           <li>Undo editing in text fields, including in the composer</li>
+          <li>Conversation loading performance improvements</li>
           <li>App-wide notification preferences now handled by desktop</li>
           <li>Improved missing attachment detection in composer</li>
           <li>Initial plugin system</li>