NEWS.rst: remove redundant descriptions of security fixes.

Signed-off-by: Daira Hopwood <david-sarah@jacaranda.org>
Change web-API to support t=relink instead of t-move (+ docs and tests). fixes #1732

Signed-off-by: Daira Hopwood <david-sarah@jacaranda.org>
docs/frontends/webapi.rst: cosmetics.

Signed-off-by: Daira Hopwood <david-sarah@jacaranda.org>