Linkify config documentation. (#14003)

changelog.d/14003.doc

@@ -0,0 +1 @@
+Linkify urls in config documentation.

docs/usage/configuration/config_documentation.md

@@ -179,7 +179,7 @@ This will tell other servers to send traffic to port 443 instead.
 
 This option currently defaults to false.
 
-See https://matrix-org.github.io/synapse/latest/delegate.html for more
+See [Delegation of incoming federation traffic](../../delegate.md) for more
 information.
 
 Example configuration:
@@ -2977,7 +2977,7 @@ Options for each entry include:
 
  * `module`: The class name of a custom mapping module. Default is
  `synapse.handlers.oidc.JinjaOidcMappingProvider`.
- See https://matrix-org.github.io/synapse/latest/sso_mapping_providers.html#openid-mapping-providers
+ See [OpenID Mapping Providers](../../sso_mapping_providers.md#openid-mapping-providers)
  for information on implementing a custom mapping provider.
 
  * `config`: Configuration for the mapping provider module. This section will
@@ -3418,13 +3418,15 @@ This option has the following sub-options:
  the user directory. If false, search results will only contain users
  visible in public rooms and users sharing a room with the requester.
  Defaults to false.
+
  NB. If you set this to true, and the last time the user_directory search
  indexes were (re)built was before Synapse 1.44, you'll have to
  rebuild the indexes in order to search through all known users.
+
  These indexes are built the first time Synapse starts; admins can
- manually trigger a rebuild via API following the instructions at
-  https://matrix-org.github.io/synapse/latest/usage/administration/admin_api/background_updates.html#run
- Set to true to return search results containing all known users, even if that
+ manually trigger a rebuild via the API following the instructions
+ [for running background updates](../administration/admin_api/background_updates.md#run),
+ set to true to return search results containing all known users, even if that
  user does not share a room with the requester.
 * `prefer_local_users`: Defines whether to prefer local users in search query results.
  If set to true, local users are more likely to appear above remote users when searching the