refactor: Replace 'pm' with 'dm'.

Author: Ajnus

docs/developer-feature-tutorial.md

@@ -113,7 +113,7 @@ To check for the above conditions, we create a function in `ui.py`:
 ```python
 
     def handle_typing_event(self, event: Dict['str', Any]) -> None:
-        # If the user is in pm narrow with the person typing
+        # If the user is in dm narrow with the person typing
         if len(self.model.narrow) == 1 and\
                 self.model.narrow[0][0] == 'pm_with' and\
                 event['sender']['email'] in self.model.narrow[0][1].split(','):

docs/getting-started-imgs/raw/send-pm-autocomplete1-raw.png renamed to docs/getting-started-imgs/raw/send-dm-autocomplete1-raw.png

@@ -138,7 +138,7 @@ If you want to show you agree with the current message, type <kbd>+</kbd> to add
 
 Let's try sending a direct message to the author of a message. Select the message you sent to the [#test here](https://chat.zulip.org/#narrow/stream/7-test-here) stream earlier and press <kbd>shift</kbd><kbd>r</kbd> to send a direct message to yourself. Type your message in the message editor that appears at the bottom of the middle column and then type <kbd>ctrl</kbd><kbd>d</kbd> to send. Press the <kbd>shift</kbd><kbd>p</kbd> hotkey as we did earlier in the tutorial to narrow to your direct messages and make sure everything worked properly.
 
-<img src="getting-started-imgs/send-pm.png" width="85%">
+<img src="getting-started-imgs/send-dm.png" width="85%">
 
 ### Send a Direct Message to Someone New
 
@@ -159,8 +159,8 @@ Try following the steps above to send a message to the Welcome Bot!
 
 > It's best to use <kbd>ctrl</kbd><kbd>f</kbd> to autocomplete the name and Zulip address of the person (or bot) you want to message; if you just type in their full name, Zulip Terminal does not know for sure who you are trying to send to - and there may be multiple people with that name!
 
-<img src="getting-started-imgs/send-pm-autocomplete1.png" width="85%">
-<img src="getting-started-imgs/send-pm-autocomplete2.png" width="85%">
+<img src="getting-started-imgs/send-dm-autocomplete1.png" width="85%">
+<img src="getting-started-imgs/send-dm-autocomplete2.png" width="85%">
 
 ### Create a New Topic
 

docs/getting-started-imgs/raw/send-pm-autocomplete2-raw.png renamed to docs/getting-started-imgs/raw/send-dm-autocomplete2-raw.png

@@ -206,11 +206,11 @@ def update_unreads(unreads: Dict[KeyT, int], key: KeyT) -> None:
                 unread_counts["unread_topics"], (stream_id, message["subject"])
             )
             update_unreads(unread_counts["streams"], stream_id)
-        # self-pm has only one display_recipient
+        # self-dm has only one display_recipient
         # 1-1 pms have 2 display_recipient
         elif len(message["display_recipient"]) <= 2:
             update_unreads(unread_counts["unread_pms"], message["sender_id"])
-        else:  # If it's a group pm
+        else:  # If it's a group dm
             update_unreads(
                 unread_counts["unread_huddles"],
                 frozenset(

docs/getting-started-imgs/raw/send-pm-raw.png renamed to docs/getting-started-imgs/raw/send-dm-raw.png

@@ -1568,7 +1568,7 @@ def _handle_typing_event(self, event: Event) -> None:
         sender_email = event["sender"]["email"]
         sender_id = event["sender"]["user_id"]
 
-        # If the user is in pm narrow with the person typing
+        # If the user is in dm narrow with the person typing
         # and the person typing isn't the user themselves
         if (
             len(narrow) == 1