compile: fix flag values

gtk builder does not support combining interger values with | in flags
properties, so the short names are used instead.

blueprintcompiler/language/values.py

@@ -216,7 +216,7 @@ class Flag(AstNode):
         if not isinstance(type, Enumeration):
             return None
         elif member := type.members.get(self.name):
-            return member.value
+            return member.name
         else:
             return None
 

tests/samples/flags.ui

@@ -7,7 +7,7 @@ corresponding .blp file and regenerate this file with blueprint-compiler.
 <interface>
   <requires lib="gtk" version="4.0"/>
   <object class="GApplication">
-    <property name="flags">1|4</property>
+    <property name="flags">is_service|handles_open</property>
   </object>
   <object class="GtkEventControllerScroll">
     <property name="flags">1</property>