fix(docs[redirects]): remove dirhtml-conflicting redirect entries

why: With dirhtml builder, source files like X.md and X/index.md both
produce X/index.html. Redirects between them cause rediraffe conflicts
("already exists" warnings that fail the build).
what:
- Comment out redirect entries where source and target produce the
  same dirhtml output path

Author: tony

docs/redirects.txt

@@ -1,2 +1,2 @@
-"cli.md" "cli/index.md"
-"api.md" "api/index.md"
+# "cli.md" "cli/index.md"  # dirhtml: same output path
+# "api.md" "api/index.md"  # dirhtml: same output path