[libadwaita] doc: Fix class link

[Alexander Mikhaylenko <alexm src gnome org>]

commit facaa00ccba548b31608d6d746f25fda1ba48af4
Author: Romain Vigier <romain romainvigier fr>
Date:   Fri Sep 24 12:56:47 2021 +0200

    doc: Fix class link
    
    The link was put between code marks, displaying its actual HTML code.

 doc/migrating-libhandy-1-4-to-libadwaita.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/doc/migrating-libhandy-1-4-to-libadwaita.md b/doc/migrating-libhandy-1-4-to-libadwaita.md
index b5806cb0..dc0578e8 100644
--- a/doc/migrating-libhandy-1-4-to-libadwaita.md
+++ b/doc/migrating-libhandy-1-4-to-libadwaita.md
@@ -377,7 +377,7 @@ If you had menu buttons containing an icon and a dropdown arrow, switch to
 
 ### Adjusting Text-only Buttons
 
-If you had text-only buttons, consider using `[class@Adw.ButtonContent]`. For
+If you had text-only buttons, consider using [class@Adw.ButtonContent]. For
 example, the following button:
 
 ```xml