[Migrate]: Notifications

[imath]

Link to the existing BP Codex page.

https://codex.buddypress.org/administrator-guide/notifications/

What needs to be done?

Screenshots need to be updated. Events generating a notification need to be updated. Information about extending notifications can be skipped

Handbook to migrate the page in

buddypress/docs/user

Tasks to accomplish

• This task has been added to the "Todo" panel of the Documentation project.
• The corresponding line of the data/README.md Pages list has been marked as "Migrate issue/task created".
• A PR has been submitted to the BuddyPress GH repository, it has been linked to this issue/task & the task was moved to the "In progress" panel of the Documentation project.
• The PR has been converted to a SVN patch and committed to the BuddyPress SVN repository & the task was moved to the "Done" panel of the Documentation project.