Merge pull request #4730 from YosysHQ/krys/downstream-docs

Improvements for downstream-distro maintainability.

Author: KrystalDelusion

docs/source/conf.py

@@ -56,6 +56,9 @@
     else:
         release = yosys_ver
         todo_include_todos = False
+elif os.getenv("YOSYS_DOCS_RELEASE") is not None:
+    release = yosys_ver
+    todo_include_todos = False
 else:
     release = yosys_ver
     todo_include_todos = True
@@ -87,5 +90,9 @@ def setup(app: Sphinx) -> None:
     from util.RtlilLexer import RtlilLexer
     app.add_lexer("RTLIL", RtlilLexer)
 
-    from furo_ys.lexers.YoscryptLexer import YoscryptLexer
-    app.add_lexer("yoscrypt", YoscryptLexer)
+    try:
+        from furo_ys.lexers.YoscryptLexer import YoscryptLexer
+        app.add_lexer("yoscrypt", YoscryptLexer)
+    except ModuleNotFoundError:
+        from pygments.lexers.special import TextLexer
+        app.add_lexer("yoscrypt", TextLexer)