Issue #3105975 by Hardik_Patel_12: t() calls should be avoided in classes, use...

Issue #3105975 by Hardik_Patel_12: t() calls should be avoided in classes, use dependency injection and $this->t() instead in block module

core/modules/block/src/BlockForm.php

@@ -166,7 +166,7 @@ public function form(array $form, FormStateInterface $form_state) {
       $form['theme'] = [
         '#type' => 'select',
         '#options' => $theme_options,
-        '#title' => t('Theme'),
+        '#title' => $this->t('Theme'),
         '#default_value' => $theme,
         '#ajax' => [
           'callback' => '::themeSwitch',