Docs: Fix links for view/edit source

docs/source/conf.py

@@ -11,6 +11,29 @@
 # select HTML theme
 html_theme = 'furo-ys'
 html_css_files = ['custom.css']
+html_theme_options: dict[str] = {
+    "source_repository": "/~https://github.com/YosysHQ/yosys/",
+    "source_branch": "main",
+    "source_directory": "docs/",
+}
+
+# try to fix the readthedocs detection
+html_context: dict[str] = {
+    "READTHEDOCS": True,
+    "display_github": True,
+    "github_user": "YosysHQ",
+    "github_repo": "yosys",
+    "slug": "yosys",
+}
+
+# override source_branch if not main
+git_slug = os.getenv("READTHEDOCS_VERSION_NAME")
+if git_slug not in [None, "latest", "stable"]:
+    html_theme_options["source_branch"] = git_slug
+
+# edit only works on branches, not tags
+if os.getenv("READTHEDOCS_VERSION_TYPE", "branch") != "branch":
+        html_theme_options["top_of_page_buttons"] = ["view"]
 
 # These folders are copied to the documentation's HTML output
 html_static_path = ['_static', "_images"]