[Migrate]: BP_Attachment

[imath]

Link to the existing BP Codex page.

https://codex.buddypress.org/plugindev/bp_attachment/

What needs to be done?

There should be not much to add to this page. But it needs to be checked as we may have added new methods to the API.

Handbook to migrate the page in

buddypress/docs/developer

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.