Improve accessibility text for contact search icon

Based on a suggestion on Transifex.

src/main/resources/strings/BriarDesktop.properties

@@ -4,7 +4,7 @@ access.contacts.add=Add contact
 access.contact.menu=Show contact menu
 access.contacts.dropdown.connections.expand=Expand connections menu
 access.contacts.dropdown.contacts.expand=Expand contacts menu
-access.contacts.search=Icon search contacts
+access.contacts.search=Icon for searching contacts
 access.introduction.back.contact=Go back to contact screen of introduction process
 access.introduction.close=Close introduction screen
 access.message.send=Send message