Taxon photos: add text to display the ability to add an observation directly

Platform(s), such as mobile, website, API, other:

URLs (aka web addresses) of any pages, if relevant:
any taxon page

Description of need:
Describe the iNaturalist community need that your requested feature addresses. Include screenshots, URLs, and other details to help us all understand the issue.

From several recent forum threads, it appears many users are unware that they can enter an observation number directly into the search bar when choosing taxon photos

Feature request details:
In detail, describe the feature you are requesting. This includes its functionality, where the feature is implemented, and what it might look like. Screenshots or mock-ups are helpful. The idea is to have a concrete and actionable request which the community can discuss and vote on. It might change through discussion, but it’s much easier to iterate and talk about something specific.

I think text should be displayed in the search bar indicating that users can add an observation directly.