docs(dgw): describe the provisioning view by its contract, not its caller

Reword the `ProvisionedConnection` and `ProvisioningStore::get` docs to state the
contract (credentials required, connection options optional, TTL lifetime) instead
of naming the RDP credential-injection caller, which overfits and goes stale as
soon as another consumer appears.

Author: irvingoujAtDevolution

devolutions-gateway/src/provisioning.rs

@@ -10,10 +10,10 @@ use uuid::Uuid;
 use crate::credential::{AppCredentials, CleartextAppCredentials};
 use crate::target_connection_options::TargetConnectionOptions;
 
-/// A combined, point-in-time view of everything provisioned for a session.
+/// A combined, point-in-time view of everything provisioned for a session, assembled on read from
+/// the two independent stores.
 ///
-/// Assembled on read from the two independent stores. Credentials are required by the only consumer
-/// today (RDP credential injection); connection options are optional and may be absent — never
+/// Credentials are always present; connection options are optional and may be absent — never
 /// provisioned, or expired before the credentials half.
 #[derive(Debug, Clone)]
 pub(crate) struct ProvisionedConnection {
@@ -94,12 +94,13 @@ impl ProvisioningStore {
         self.connection_options.lock().insert(jti, entry).is_some()
     }
 
-    /// Combined view for the RDP credential-injection path.
+    /// Assemble the provisioned view for a session.
     ///
-    /// Requires the credentials half and folds in the connection-options half when it is present.
-    /// Entries live until their TTL, not until first use: a jti names a session, and the token layer
-    /// allows an RDP session to open several connections (reconnects), each of which needs the same
-    /// materials. Either half is treated as absent once expired; the cleanup task reclaims them.
+    /// Returns `None` unless the credentials half is present and live; folds in the connection-options
+    /// half when it too is present. Entries live until their TTL, not until first use: a jti names a
+    /// session, and the token layer allows several connections per session (reconnects), each of which
+    /// needs the same materials. Either half is treated as absent once expired; the cleanup task
+    /// reclaims them.
     pub(crate) fn get(&self, jti: Uuid) -> Option<ProvisionedConnection> {
         let now = time::OffsetDateTime::now_utc();