Fix build warnings

src/engine/api/geary-folder-path.vala

@@ -321,7 +321,6 @@ public class Geary.FolderRoot : FolderPath {
     /**
      * The default case sensitivity of descendant folders.
      *
-     * @see FolderRoot.case_sensitive
      * @see FolderPath.get_child
      */
     public bool default_case_sensitivity { get; private set; }

src/engine/imap-engine/imap-engine-generic-account.vala

@@ -857,11 +857,6 @@ private abstract class Geary.ImapEngine.GenericAccount : Geary.Account {
         schedule_unseen_update(folder);
     }
 
-    /** Fires a {@link Account.report_problem} signal for an IMAP service. */
-    protected void notify_imap_problem(Geary.ProblemType type, Error? err) {
-        notify_service_problem(type, this.information.incoming, err);
-    }
-
     /**
      * Hooks up and queues an {@link UpdateRemoteFolders} operation.
      */

src/engine/imap-engine/imap-engine-replay-operation.vala

@@ -144,11 +144,6 @@ private abstract class Geary.ImapEngine.ReplayOperation : Geary.BaseObject, Gee.
      *
      * If an error is thrown, {@link backout_local_async} will be
      * executed only if scope is LOCAL_AND_REMOTE.
-     *
-     * @return {@link Status.COMPLETED} if the operation has completed
-     * and no further calls should be made, else {@link
-     * Status.CONTINUE} if treated as `COMPLETED`.
-     *
      */
     public virtual async void replay_remote_async(Imap.FolderSession remote)
         throws GLib.Error {