[config-ref] skip options marked as disable

The common configurations are described in the common
configurations table. The corresponding configutations
at each table are not necessary.

Change-Id: Ied2d03d1c7f71f5712fcf57d4499e127db327b7d
Implements: blueprint config-ref-common-sections

autogenerate_config_docs/autohelp.py

@@ -438,6 +438,11 @@ def write_files(package_name, options, target, output_format):
             'items': [],
         }
 
+        # Skip the options that is explicitly marked as disabled,
+        # which is used for common configuration options.
+        if cat == 'disable':
+            continue
+
         if cat in category_names:
             env['nice_cat'] = category_names[cat]
         else: