[gnome-builder] tree: fix comment typo

[Christian Hergert <chergert src gnome org>]

commit 5f5392bb30da253decd59ee2d8df0d136e286d26
Author: Christian Hergert <chergert redhat com>
Date:   Fri Jun 28 15:08:51 2019 -0700

    tree: fix comment typo

 src/libide/tree/ide-tree-model.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/libide/tree/ide-tree-model.c b/src/libide/tree/ide-tree-model.c
index 7ff90de8b..9d78dde40 100644
--- a/src/libide/tree/ide-tree-model.c
+++ b/src/libide/tree/ide-tree-model.c
@@ -338,7 +338,7 @@ ide_tree_model_class_init (IdeTreeModelClass *klass)
    * tree contents.
    *
    * For example, to extend the project-tree, plugins should set
-   * "X-Tree-Kind=project" in their .plugin manifest.
+   * "X-Tree-Kind=project-tree" in their .plugin manifest.
    *
    * Since: 3.32
    */