refactor: Rename remaining bugdown refrences to markdown in actions.py.

This commit removes bugdown alias and do proper imports from markdown
module. Also remove bugdown word and replace it with markdown in
comments.
This commit is part of series of commits aimed at renaming bugdown to
markdown.

zerver/lib/actions.py

@@ -49,7 +49,6 @@ from confirmation.models import (
     generate_key,
 )
 from zerver.decorator import statsd_increment
-from zerver.lib import markdown as bugdown
 from zerver.lib import retention as retention
 from zerver.lib.addressee import Addressee
 from zerver.lib.alert_words import (
@@ -96,6 +95,7 @@ from zerver.lib.export import get_realm_exports_serialized
 from zerver.lib.external_accounts import DEFAULT_EXTERNAL_ACCOUNTS
 from zerver.lib.hotspots import get_next_hotspots
 from zerver.lib.i18n import get_language_name
+from zerver.lib.markdown import MentionData, topic_links
 from zerver.lib.markdown import version as markdown_version
 from zerver.lib.message import (
     MessageDict,
@@ -1044,7 +1044,7 @@ def render_incoming_message(message: Message,
                             content: str,
                             user_ids: Set[int],
                             realm: Realm,
-                            mention_data: Optional[bugdown.MentionData]=None,
+                            mention_data: Optional[MentionData]=None,
                             email_gateway: bool=False) -> str:
     realm_alert_words_automaton = get_alert_word_automaton(realm)
     try:
@@ -1166,7 +1166,7 @@ def get_recipient_info(recipient: Recipient,
     message_to_user_id_set = set(message_to_user_ids)
 
     user_ids = set(message_to_user_id_set)
-    # Important note: Because we haven't rendered bugdown yet, we
+    # Important note: Because we haven't rendered markdown yet, we
     # don't yet know which of these possibly-mentioned users was
     # actually mentioned in the message (in other words, the
     # mention syntax might have been in a code block or otherwise
@@ -1240,7 +1240,7 @@ def get_recipient_info(recipient: Recipient,
     # mentioned in it, and so can't use get_ids_for.
     #
     # Further in the do_send_messages code path, once
-    # `mentioned_user_ids` has been computed via bugdown, we'll filter
+    # `mentioned_user_ids` has been computed via markdown, we'll filter
     # these data structures for just those users who are either a
     # direct recipient or were mentioned; for now, we're just making
     # sure we have the data we need for that without extra database
@@ -1386,7 +1386,7 @@ def do_send_messages(messages_maybe_none: Sequence[Optional[MutableMapping[str,
         message['sender_queue_id'] = message.get('sender_queue_id', None)
         message['realm'] = message.get('realm', message['message'].sender.realm)
 
-        mention_data = bugdown.MentionData(
+        mention_data = MentionData(
             realm_id=message['realm'].id,
             content=message['message'].content,
         )
@@ -1645,7 +1645,7 @@ def create_user_messages(message: Message,
         ums_to_create.append(um)
 
     # These properties on the Message are set via
-    # render_markdown by code in the bugdown inline patterns
+    # render_markdown by code in the markdown inline patterns
     wildcard = message.mentions_wildcard
     ids_with_alert_words = message.user_ids_with_alert_words
 
@@ -4427,7 +4427,7 @@ def do_update_message(user_profile: UserProfile, message: Message,
                       propagate_mode: str, send_notification_to_old_thread: bool,
                       send_notification_to_new_thread: bool, content: Optional[str],
                       rendered_content: Optional[str], prior_mention_user_ids: Set[int],
-                      mention_user_ids: Set[int], mention_data: Optional[bugdown.MentionData]=None) -> int:
+                      mention_user_ids: Set[int], mention_data: Optional[MentionData]=None) -> int:
     """
     The main function for message editing.  A message edit event can
     modify:
@@ -4499,7 +4499,7 @@ def do_update_message(user_profile: UserProfile, message: Message,
         event['is_me_message'] = Message.is_status_message(content, rendered_content)
 
         # message.has_image and message.has_link will have been
-        # already updated by bugdown rendering in the caller.
+        # already updated by markdown rendering in the caller.
         message.has_attachment = check_attachment_reference_change(message)
 
         if message.is_stream_message():
@@ -4582,7 +4582,7 @@ def do_update_message(user_profile: UserProfile, message: Message,
         # These fields have legacy field names.
         event[ORIG_TOPIC] = orig_topic_name
         event[TOPIC_NAME] = topic_name
-        event[TOPIC_LINKS] = bugdown.topic_links(message.sender.realm_id, topic_name)
+        event[TOPIC_LINKS] = topic_links(message.sender.realm_id, topic_name)
         edit_history_event[LEGACY_PREV_TOPIC] = orig_topic_name
 
     if propagate_mode in ["change_later", "change_all"]: