Query builder: making it clear how to query for multiple activity identifiers

[stevieflow]

The interface does not indicate how to query for multiple identifiers - such as

https://datastore.codeforiati.org/api/1/access/transaction.xlsx?iati-identifier=XM-DAC-47066-CD.0071|XM-DAC-47066-DP.0843

Underneath the search box we have the text:

Search for an activity containing a specific IATI Identifier (similar to a project code).

Suggest we just amend this to

Search for an activity containing a specific IATI Identifier (similar to a project code). For multiple activities, use the | character, eg: ACTIVITY-123|ACTIVITY-456|ACTIVITY-789

..or something similar

Note - I don't know if the functionality exists to paste in a group of comma-separated identifiers, which then form defined items in the search bar - as with sector:

That might be helpful, but could in turn create a few UI/UX headaches

Suggest the simple text addition for now @markbrough