Focus a tab when attempting to close it with unsaved changes

In most cases you want to see the contents of the tab before deciding what to
respond to the dialog that pops up. This is typical behavior in other editors
such as Sublime.

Closes https://github.com/linuxmint/xed/issues/95

xed/xed-commands-file.c

@@ -47,7 +47,6 @@
 #include "xed-file-chooser-dialog.h"
 #include "xed-close-confirmation-dialog.h"
 
-
 /* Defined constants */
 #define XED_OPEN_DIALOG_KEY         "xed-open-dialog-key"
 #define XED_TAB_TO_SAVE_AS          "xed-tab-to-save-as"
@@ -1535,7 +1534,9 @@ tab_can_close (XedTab  *tab,
 
     if (!_xed_tab_can_close (tab))
     {
-        GtkWidget     *dlg;
+        GtkWidget *dlg;
+
+        xed_window_set_active_tab (XED_WINDOW (window), tab);
 
         dlg = xed_close_confirmation_dialog_new_single (window, doc, FALSE);