(secrets-search-items, secrets-create-item)
(secrets-get-attributes, secrets-expand-item): Attributes will be
stored on the password database without leading ":", as all other
clients do as well.
(secrets-mode): Fix docstring.
(secrets-show-secrets): Provide it as autoloaded command only when
D-Bus support is available. Check existence of Secret Service API.
* net/secrets.el (secrets-mode): New major mode.
(secrets-show-secrets, secrets-show-collections)
(secrets-expand-collection, secrets-expand-item)
(secrets-tree-widget-after-toggle-function)
(secrets-tree-widget-show-password): New defuns.
