Fix links to Synapse Admin API docs

Point to the new repository maintained by Element instead of the one
that was under Matrix.org that was archived.

The files now also have the `.md` extension rather than `.rst`. And a
few URL fragments have changed.

Author: zecakeh

README.md

@@ -4,4 +4,4 @@
 [![docs.rs page](https://docs.rs/synapse-admin-api/badge.svg)](https://docs.rs/synapse-admin-api/)
 ![license: MIT](https://img.shields.io/crates/l/synapse-admin-api.svg)
 
-**synapse-admin-api** contains serializable types for the requests and responses for each endpoint in the [synapse admin API](https://github.com/matrix-org/synapse/tree/master/docs/admin_api).
+**synapse-admin-api** contains serializable types for the requests and responses for each endpoint in the [synapse admin API](https://github.com/element-hq/synapse/tree/master/docs/admin_api).

src/account_validity/renew_account/v1.rs

@@ -1,4 +1,4 @@
-//! [GET /_synapse/admin/v1/account_validity/validity](https://github.com/matrix-org/synapse/blob/master/docs/admin_api/account_validity.rst)
+//! [GET /_synapse/admin/v1/account_validity/validity](https://github.com/element-hq/synapse/blob/master/docs/admin_api/account_validity.md)
 
 use ruma::{
     api::{metadata, request, response, Metadata},

src/lib.rs

@@ -15,7 +15,7 @@
 //!   compiles all types as exhaustive. By enabling this feature you opt out of all semver
 //!   guarantees synapse-admin-api otherwise provides.
 //!
-//! [api]: https://github.com/matrix-org/synapse/tree/master/docs/admin_api
+//! [api]: https://github.com/element-hq/synapse/tree/master/docs/admin_api
 
 // FIXME: don't allow dead code, warn on missing docs
 #![allow(dead_code)]

src/register_users/shared_secret_register/v1.rs

@@ -1,4 +1,4 @@
-//! [POST /_synapse/admin/v1/register](https://matrix-org.github.io/synapse/latest/admin_api/register_api.html#shared-secret-registration)
+//! [POST /_synapse/admin/v1/register](https://github.com/element-hq/synapse/blob/master/docs/admin_api/register_api.md)
 
 #[cfg(feature = "shared-secret-registration-mac")]
 use hmac::{digest::InvalidLength, Hmac, Mac};
@@ -89,7 +89,7 @@ impl Response {
 
 /// Calculate the MAC based on the given inputs.
 ///
-/// See <https://matrix-org.github.io/synapse/latest/admin_api/register_api.html#shared-secret-registration> for details.
+/// See <https://github.com/element-hq/synapse/blob/master/docs/admin_api/register_api.md> for details.
 #[cfg(feature = "shared-secret-registration-mac")]
 pub fn hmac(
     registration_shared_secret: &str,

src/register_users/shared_secret_register_nonce/v1.rs

@@ -1,4 +1,4 @@
-//! [GET /_synapse/admin/v1/register](https://matrix-org.github.io/synapse/latest/admin_api/register_api.html#shared-secret-registration)
+//! [GET /_synapse/admin/v1/register](https://github.com/element-hq/synapse/blob/master/docs/admin_api/register_api.md)
 
 use ruma::api::{metadata, request, response, Metadata};
 

src/users/create_or_modify/v2.rs

@@ -1,4 +1,4 @@
-//! [PUT /_synapse/admin/v2/users/:user_id](https://github.com/matrix-org/synapse/blob/master/docs/admin_api/user_admin_api.rst#create-or-modify-account)
+//! [PUT /_synapse/admin/v2/users/:user_id](https://github.com/element-hq/synapse/blob/master/docs/admin_api/user_admin_api.md#create-or-modify-account)
 
 use ruma::{
     api::{metadata, request, response, Metadata},

src/users/deactivate_account/v1.rs

@@ -1,4 +1,4 @@
-//! [POST /_synapse/admin/v1/deactivate/:user_id](https://github.com/matrix-org/synapse/blob/develop/docs/admin_api/user_admin_api.rst#deactivate-account)
+//! [POST /_synapse/admin/v1/deactivate/:user_id](https://github.com/element-hq/synapse/blob/develop/docs/admin_api/user_admin_api.md#deactivate-account)
 
 use ruma::{
     api::{metadata, request, response, Metadata},

src/users/get_details/v2.rs

@@ -1,4 +1,4 @@
-//! [GET /_synapse/admin/v2/users/:user_id](https://github.com/matrix-org/synapse/blob/master/docs/admin_api/user_admin_api.rst#query-user-account)
+//! [GET /_synapse/admin/v2/users/:user_id](https://github.com/element-hq/synapse/blob/master/docs/admin_api/user_admin_api.md#query-user-account)
 
 use ruma::{
     api::{metadata, request, response, Metadata},

src/users/is_user_admin/v1.rs

@@ -1,4 +1,4 @@
-//! [GET /_synapse/admin/v1/users/:user_id/admin](https://github.com/matrix-org/synapse/blob/master/docs/admin_api/user_admin_api.rst#get-whether-a-user-is-a-server-administrator-or-not)
+//! [GET /_synapse/admin/v1/users/:user_id/admin](https://github.com/element-hq/synapse/blob/master/docs/admin_api/user_admin_api.md#get-whether-a-user-is-a-server-administrator-or-not)
 
 use ruma::{
     api::{metadata, request, response, Metadata},

src/users/list_joined_rooms/v1.rs

@@ -1,4 +1,4 @@
-//! [GET /_synapse/admin/v1/users/:user_id/joined_rooms](https://github.com/matrix-org/synapse/blob/master/docs/admin_api/user_admin_api.rst#list-room-memberships-of-an-user)
+//! [GET /_synapse/admin/v1/users/:user_id/joined_rooms](https://github.com/element-hq/synapse/blob/master/docs/admin_api/user_admin_api.md#list-joined-rooms-of-a-user)
 
 use ruma::{
     api::{metadata, request, response, Metadata},