Only build htmlzip on RTD, fix do-nothing

Author: felix-hilden

.readthedocs.yaml

@@ -5,7 +5,8 @@ sphinx:
   configuration: docs/src/conf.py
   fail_on_warning: false
 
-formats: all
+formats:
+  - htmlzip
 
 python:
   version: "3.8"

src/sphinx_codeautolink/extension/__init__.py

@@ -65,7 +65,7 @@ def parse_blocks(self, app, doctree):
 
     def once_on_doctree_resolved(self, app):
         """Clean source transforms and create code references."""
-        if self.code_refs:
+        if self.code_refs or self.do_nothing:
             return
 
         for transforms in self.cache.transforms.values():