Only bold number of shown entries if found in the translated string

This should fix the following crash:

```
Exception java.lang.IndexOutOfBoundsException: setSpan (-1 ... 0) starts before 0
  at android.text.SpannableStringInternal.checkRange (SpannableStringInternal.java:499)
  at android.text.SpannableStringInternal.setSpan (SpannableStringInternal.java:199)
  at android.text.SpannableStringInternal.setSpan (SpannableStringInternal.java:186)
  at android.text.SpannableString.setSpan (SpannableString.java:60)
  at com.beemdevelopment.aegis.ui.views.EntryAdapter$FooterView.refresh (EntryAdapter.java:596)
```

app/src/main/java/com/beemdevelopment/aegis/ui/views/EntryAdapter.java

@@ -17,10 +17,10 @@ import android.widget.TextView;
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
 
-import com.beemdevelopment.aegis.CopyBehavior;
 import com.beemdevelopment.aegis.AccountNamePosition;
-import com.beemdevelopment.aegis.R;
+import com.beemdevelopment.aegis.CopyBehavior;
 import com.beemdevelopment.aegis.Preferences;
+import com.beemdevelopment.aegis.R;
 import com.beemdevelopment.aegis.SortCategory;
 import com.beemdevelopment.aegis.ViewMode;
 import com.beemdevelopment.aegis.helpers.ItemTouchHelperAdapter;
@@ -777,8 +777,10 @@ public class EntryAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>
 
             String entriesShownString = String.format("%d", entriesShown);
             int spanStart = entriesShownSpannable.toString().indexOf(entriesShownString);
+            if (spanStart >= 0) {
                 int spanEnd = spanStart + entriesShownString.length();
                 entriesShownSpannable.setSpan(new StyleSpan(Typeface.BOLD), spanStart, spanEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
+            }
 
             TextView textView = _footerView.findViewById(R.id.entries_shown_count);
             textView.setText(entriesShownSpannable);