explain that a requirement caused the error, otherwise you search until you die

Signed-off-by: Nico Schottelius <nico@bento.schottelius.org>
remove some old typos and omit type details that follow anyway

Signed-off-by: Nico Schottelius <nico@bento.schottelius.org>
++changes

Signed-off-by: Nico Schottelius <nico@bento.schottelius.org>