Log Message:
snac: update to 2.58. Changes:

Search by content also looks into alt-text from attachments (images,
videos, etc.).

Search by content is case insensitive for all Unicode-supported
alphabets (previously was only for ASCII characters).

Added support for bookmarking posts.

Fixed a failed compilation under Solaris/Illumos.

The actor `Person` object now includes a `featured` property, that
returns the list of pinned posts.

The delete post button can now be hidden server-wise (it's not very
useful and clutters the space).

The lists of pinned and bookmarked posts are directly accesible from the
private timeline.