[fa] Add remaining i18n entries

[chalin]

Navigate to https://example.docsy.dev/fa/docs/, and you'll see a few [i18n] placeholder strings. At least those used in these Persian pages should be fixed.

[chalin]

@theletterf - I was wondering if you could help with this when you have a moment? As mentioned in the opening comment, at least to address those entries that are currently being used in the Persian pages.

[theletterf]

With the help of Google translate and some independent checks:

• post_view_this should be مشاهده منبع صفحه
• Feeback should be بازخورد
• Was this page helpful should be این صفحه به شما کمک کرد؟
• Yes and No buttons should be آره and نه respectively (notice that نه is the informal way of "no". You'd use بله for yes andخیر for something more formal, but I wager our users prefer the informal form).