translation: Add Urdu translation guide.

docs/translating/index.md

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 polish
 russian
 spanish
+urdu
 ```

docs/translating/urdu.md

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+# Urdu translation style guide(انداذِ ترجمہ کا رہنما)
+
+Use semi-formal Urdu for translation:
+
+- Formal "you" (_آپ_) instead of informal form _تم_. Many top software
+  companies (e.g. Google, Facebook, Microsoft) use the formal one, because it's typically
+  considered rude to use the informal one without an established acquaintance with someone.
+
+- Imperative, active, and continuous verbs, e.g. _manage streams_ -
+  _سٹریمس کی رہنمائ کریں_, not _سٹریمس کی رہنمائ_.
+
+- Warm and friendly phrasing whenever appropriate.
+
+- No slang or regional phrases that could be unclear or too informal.
+
+- Balance common verbs and nouns with specific IT-related translations
+  of English terms - this can be tricky, try to check how other
+  resources were translated (e.g. Gmail, Microsoft websites, Facebook)
+  to decide what wouldn't sound awkward/rude in Urdu.
+
+Some terms are very tricky to translate, so be sure to communicate
+with other Urdu speakers in the community. It's all about making
+Zulip friendly and usable.
+
+## Terms(اصطلاحات)
+
+- Message - **پیغام**
+- Private message (PM) - **ذاتی پیغام**
+- Stream - **سٹریم**
+- Topic - **موضوع**
+- Private/invite-only stream - **ذاتی / دعوت کی ضرورت والی سٹریم**
+- Public stream - **عوامی سٹریم**
+- Bot - **بوٹ**
+- Integration - **انضمام**
+- Notification - **اطلاع**
+- Alert word - **الفاظِ چوکس**: this literally translate to "word(s) to remain vigilant of".
+- View - **دیکھیں**
+- Filter - **فلٹر**: as used with narrowing (see below).
+- Home - **ھُوم**: using the literal translation--"گھر" (literally home)--would seem out of place.
+- Emoji - **ایموجی**
+
+## Phrases (فِقْرے)
+
+- Narrow to - **محدود کریں**: the literal Urdu translation is "تنگ کریں" which may end up being
+  interpreted as its more common meaning which is incorrect here. The correct phrase is
+  "محدود کریں".
+- Subscribe/Unsubscribe to a stream - **سٹریم کو سبسکرائب ی / اَنسبسکرائب**
+- Mute/Unmute - **خاموش کریں / نا خاموسش کریں**
+- Deactivate/Reactivate - **فعال کریں/غیر فعال کریں**
+- Search - **تلاش کریں**
+- Pin - **پن کریں**
+- Mention/@mention - **زکر کریں / @زکر کریں**
+- Invalid - **غلط**
+- Customization - **ضرورت کے مطابق بنانا**
+- I want - **مجھےچاھءے**
+- User - **صارف**
+- Person/People - **شخص / لوگ**
+
+## Others(مختلف دیگر)
+
+- We - **ہم**
+- Message table - **پیغام بورڈ**
+- Enter/Intro - **تعارف / درج**