Improve the accessibility of the search field

Problem/Motivation

At the moment if you enter a search term into the search field the query is submitted without the need of pressing the return key and the search results underneath are updated accordingly. That is happening unexpected to the user, which is not in line with WCAG 2.2 SC 3.2.2 https://www.w3.org/WAI/WCAG22/Understanding/on-input.html

Steps to reproduce

• go to /admin/modules/browse
• enter something into the search field without pressing the return key at the end

Proposed resolution

There are two options to either inform the user upfront or adding a submit button. I would vote for the latter and apply a behavior that if you press the return key while the search field is still being active or if you press the submit button a new search is triggered (a pattern for example amazon uses).