Co-authored-by: reivilibre <olivier@librepush.net>

Users admin API can now also modify user
type in addition to allowing it to be
set on user creation.

Signed-off-by: Jason Robinson <jasonr@matrix.org>
Co-authored-by: Brendan Abolivier <babolivier@matrix.org>

Signed-off-by: Dirk Klimpel <dirk@klimpel.org>

This adds a new API GET /_synapse/admin/v1/username_available?username=foo to check if a username is available. It is the counterpart to https://matrix.org/docs/spec/client_server/r0.6.0#get-matrix-client-r0-register-available, except that it works even if registration is disabled.

Signed-off-by: Dirk Klimpel <dirk@klimpel.org>

Related to #10251

* Fix broken links in documentation

* newsfile

So that they render nicely in mdbook (see #10086), and so that we no longer have a mix of structured text languages in our documentation (excluding files outside of `docs/`).