Replace R.string.yes with R.string.ok

Android doesn't use yes/no but ok/cancel usually, so this should be done here, too

app/src/main/res/values-bg/strings.xml

@@ -75,7 +75,6 @@
     <string name="downloads_title">Изтегляния</string>
     <string name="error_report_title">Съобщение за грешка</string>
     <string name="all">Всички</string>
-    <string name="yes">Да</string>
     <string name="disabled">Забранено</string>
     <string name="clear">Изчисти</string>
     <string name="best_resolution">Най-добра резолюция</string>