add target quick search info + fix typist null in attach list

src/frontend/app/attachments/attachments-list.component.html

src/frontend/app/header/header-right.component.html

src/frontend/app/search/search-home.component.html

src/frontend/lang/lang-en.ts

src/frontend/lang/lang-fr.ts

src/frontend/lang/lang-nl.ts