fix: make maintainer tool output actionable

--emulator accepts a buildbot core name from a profile's cores:, and a
mistyped target gets the closest names instead of every target. diff_truth
shows destinations and reports unpaired entries as evidence, not removals.
The verify summary counts discrepancies, a shared destination names both
systems, a truth hash conflict names both cores, and pipeline steps carry
their place in the real run instead of N/8. Every GitHub API caller takes
the token from github_token(), which falls back to gh auth token.

scripts/validate_site.py

@@ -280,7 +280,11 @@ def validate_site(site: Path, config_path: Path) -> list[str]:
 
 
 def main() -> None:
-    parser = argparse.ArgumentParser(allow_abbrev=False, description=__doc__)
+    parser = argparse.ArgumentParser(
+        allow_abbrev=False,
+        description=__doc__.replace("``", ""),
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+    )
     parser.add_argument(
         "--site-dir", default="site",
         help="the built site (default: %(default)s)",