Ensure proper translation of the about dialog title

Note that GTK+ sets a default title of _("About %s") on the dialog
window (where %s is replaced by the name of the application, but
in order to ensure proper translation of the title, applications
should set the title property explicitly when constructing a
GtkAboutDialog

https://developer.gnome.org/gtk3/stable/GtkAboutDialog.html

pluma.pot

@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: MATE Desktop Environment\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-02-16 11:41+0100\n"
+"POT-Creation-Date: 2019-02-16 22:22+0100\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -1127,7 +1127,11 @@ msgid ""
 "Street, Fifth Floor, Boston, MA 02110-1301 USA"
 msgstr ""
 
-#: ../pluma/pluma-commands-help.c:102
+#: ../pluma/pluma-commands-help.c:100
+msgid "About Pluma"
+msgstr ""
+
+#: ../pluma/pluma-commands-help.c:103
 msgid ""
 "Copyright © 1998-2000 Evan Lawrence, Alex Robert\n"
 "Copyright © 2000-2002 Chema Celorio, Paolo Maggi\n"
@@ -1138,7 +1142,7 @@ msgid ""
 "Copyright © 2012-2019 MATE developers"
 msgstr ""
 
-#: ../pluma/pluma-commands-help.c:112
+#: ../pluma/pluma-commands-help.c:113
 msgid "translator-credits"
 msgstr ""
 

pluma/pluma-commands-help.c

@@ -97,6 +97,7 @@ void _pluma_cmd_help_about(GtkAction* action, PlumaWindow* window)
 
 	gtk_show_about_dialog(GTK_WINDOW(window),
 		"program-name", "Pluma",
+		"title", _("About Pluma"),
 		"authors", authors,
 		"comments", _(comments),
 		"copyright", _("Copyright \xc2\xa9 1998-2000 Evan Lawrence, Alex Robert\n"