[gi-docgen/validate-links] gir: Add missing constant types

[Emmanuele Bassi <ebassi src gnome org>]

commit 64bfb3b56869687cda700a692e945d82c7751ced
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Tue May 25 13:04:19 2021 +0100

    gir: Add missing constant types

 gidocgen/gir/ast.py | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/gidocgen/gir/ast.py b/gidocgen/gir/ast.py
index e911477..0bea25a 100644
--- a/gidocgen/gir/ast.py
+++ b/gidocgen/gir/ast.py
@@ -873,6 +873,8 @@ class Namespace:
             return self._aliases[name]
         if name in self._bitfields:
             return self._bitfields[name]
+        if name in self._constants:
+            return self._constants[name]
         if name in self._enumerations:
             return self._enumerations[name]
         if name in self._error_domains: