Update preference screen title.

- Add missing title to preference screen xml so that they will be used to
set the activity title when the fragment is launched.
- Also updated some incorrect preference screen titles.
- Overrides getTitle() in preference fragments that do not use the
preference screen xml.

Bug: 64564191
Test: blaze-bin/screenshots/android/i18nscreenshots/i18nscreenshots
Change-Id: Id72d5ddf18f0962bc484de8bbd847a2e55d6371e

src/com/android/settings/accessibility/ToggleFontSizePreferenceFragment.java

@@ -17,6 +17,7 @@
 package com.android.settings.accessibility;
 
 import android.annotation.Nullable;
+import android.annotation.StringRes;
 import android.content.ContentResolver;
 import android.content.res.Configuration;
 import android.content.res.Resources;
@@ -54,6 +55,12 @@ public class ToggleFontSizePreferenceFragment extends PreviewSeekBarPreferenceFr
         }
     }
 
+    @Override
+    @StringRes
+    protected int getTitle() {
+        return R.string.title_font_size;
+    }
+
     @Override
     protected Configuration createConfig(Configuration origConfig, int index) {
         // Populate the sample layouts.