[ghex] meson: fix docs dir for API docs

[Logan Rathbone <larathbone src gnome org>]

commit dca693f138718795159b8ec7b94df6b3275c73fa
Author: Logan Rathbone <poprocks gmail com>
Date:   Wed Dec 29 17:58:28 2021 -0500

    meson: fix docs dir for API docs

 docs/meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/docs/meson.build b/docs/meson.build
index ecbbc08..327ef27 100644
--- a/docs/meson.build
+++ b/docs/meson.build
@@ -44,6 +44,6 @@ if get_option('gtk_doc')
     command: docs_cmd,
     build_by_default: true,
     install: true,
-    install_dir: join_paths(docs_dir, gir_apiname),
+    install_dir: docs_dir,
   )
 endif