docs/metrics: use underline-style heading markup

For consistency with the other docs. This also corrects the heading
levels, since level two was skipped.

Change-Id: Iab010cfca68af7d376944b0e8b2b8c076e33fbde
1 file changed
tree: 5464dd684f79d32fef2caaa6f6c6e4a9701627c6
  1. .settings/
  2. src/
  3. .gitignore
  4. .mailmap
  5. BUILD
  6. LICENSE