[fractal] content-message-row: Use 'caption' CSS class

[Julian Sparber <jsparber src gnome org>]

commit 0cdac386ce0c3597e31ec09d6fa54502d6f552e2
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Thu Mar 31 17:44:12 2022 -0300

    content-message-row: Use 'caption' CSS class
    
    Instead of 'heading'. The original mockup [1] seems to have this label
    much more subtle, and definitely not bold.
    
    [1] https://gitlab.gnome.org/Teams/Design/app-mockups/-/raw/master/fractal/main-window.png

 data/resources/ui/content-message-row.ui | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/data/resources/ui/content-message-row.ui b/data/resources/ui/content-message-row.ui
index 63e6c2ce5..17c679553 100644
--- a/data/resources/ui/content-message-row.ui
+++ b/data/resources/ui/content-message-row.ui
@@ -32,7 +32,7 @@
                 <child type="end">
                   <object class="GtkLabel" id="timestamp">
                     <style>
-                      <class name="heading"/>
+                      <class name="caption"/>
                       <class name="timestamp"/>
                       <class name="dim-label"/>
                     </style>