Fix cppcheck failure on gettext.h

The `gettext.h` is not our code. It's comming from gettext-devel package
and we copy that into our code during autogen execution. However, new
cppcheck version 2.11 started to gave errors from this header file. It's
filed here

https://bugzilla.redhat.com/show_bug.cgi?id=2217542

To not block ourselves on an error from another library let's suppress
that error for now.

tests/cppcheck/suppression-list.txt

@@ -7,3 +7,7 @@ unusedFunction:widgets/glade/*
 // stop whining about G_DEFINE macros
 constStatement:*/widgets/src/*
 constStatement:widgets/src/*
+
+//
+returnDanglingLifetime:*widgets/src/gettext.h
+returnDanglingLifetime:widgets/src/gettext.h