After the messages have been imported, set the rendered_content of the
messages instead of leaving its value to be 'None'.
This is important to ensure that:
(1) Performance for users is good after completing the import.
(2) The database's full-text indexes have all of the imported messages
(which only happens properly when Message rows have their
rendered_content field edited).
Fixes#9168.
The gitter mentions are in the format '@usermention'
and the mentions are included in the export data as:
"mentions": [
{
"screenName": "usermention",
"userId": "54d7876c15522ed4b3dbbefb",
"userIds": []
}]
We extract this data and map this mention to @**usermention**
for Zulip.
Anders Kaseorg
Rhea Parekh