[gtkmm/gtkmm-3-24] gtk/gtkmm.h: Fix a typo

[Kjell Ahlstedt <kjellahl src gnome org>]

commit 44cab7a7e538651f30071e6e16c3f012ad6964a7
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Mon Oct 12 17:02:54 2020 +0200

    gtk/gtkmm.h: Fix a typo

 gtk/gtkmm.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/gtkmm.h b/gtk/gtkmm.h
index bded9133..bcb533f7 100644
--- a/gtk/gtkmm.h
+++ b/gtk/gtkmm.h
@@ -65,7 +65,7 @@
  * @code
  * g++ program.cc -o program  `pkg-config --cflags --libs gtkmm-3.0`
  * @endcode
- * If your version of g++ is not C++11-compliant be default,
+ * If your version of g++ is not C++11-compliant by default,
  * add the @c -std=c++11 option.
  *
  * If you use <a href="https://mesonbuild.com/";>Meson</a>, include the following