[shotwell] Fix a comment copy-paste

[Jens Georg <jensgeorg src gnome org>]

commit 0e7daf1cdea04ed5bb2ce9e33e142878ba62f863
Author: Jens Georg <mail jensge org>
Date:   Wed Oct 7 14:49:38 2020 +0200

    Fix a comment copy-paste

 src/Application.vala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/Application.vala b/src/Application.vala
index 36acc4176..a52e03138 100644
--- a/src/Application.vala
+++ b/src/Application.vala
@@ -104,7 +104,7 @@ public class Application {
     }
 
     /**
-     * @brief Signal handler for GApplication's 'command-line' signal.
+     * @brief Signal handler for GApplication's 'activate' signal.
      *
      * The most likely scenario for this to be fired is if the user
      * either tried to run us twice in library mode, or we've just gotten