flatpak enter: Add completion

This was the last command without completion, so we're complete!

app/flatpak-builtins-enter.c

@@ -271,3 +271,28 @@ flatpak_builtin_enter (int           argc,
 
   exit (status);
 }
+
+gboolean
+flatpak_complete_enter (FlatpakCompletion *completion)
+{
+  g_autoptr(GOptionContext) context = NULL;
+  g_autoptr(GError) error = NULL;
+
+  context = g_option_context_new ("");
+  if (!flatpak_option_context_parse (context, options, &completion->argc, &completion->argv, FLATPAK_BUILTIN_FLAG_NO_DIR, NULL, NULL, NULL))
+    return FALSE;
+
+  switch (completion->argc)
+    {
+    case 0:
+    case 1:
+      flatpak_complete_options (completion, global_entries);
+      flatpak_complete_options (completion, options);
+      break;
+
+    default:
+      break;
+    }
+
+  return TRUE;
+}

app/flatpak-main.c

@@ -63,7 +63,7 @@ static FlatpakCommand commands[] = {
   { "override", "Override permissions for an application", flatpak_builtin_override, flatpak_complete_override },
   { "export-file", "Grant an application access to a specific file", flatpak_builtin_export_file, flatpak_complete_export_file },
   { "make-current", "Specify default version to run", flatpak_builtin_make_current_app, flatpak_complete_make_current_app },
-  { "enter", "Enter the namespace of a running application", flatpak_builtin_enter },
+  { "enter", "Enter the namespace of a running application", flatpak_builtin_enter, flatpak_complete_enter },
 
   { "\n Manage remote repositories" },
   { "remote-add", "Add a new remote repository (by URL)", flatpak_builtin_add_remote, flatpak_complete_add_remote },