Change docs links to actual file extension (.md)

See https://gerrit-review.googlesource.com/83950 for detailed context.

Change-Id: Ia88f168c95050659a76956c7b089e005b350ce6b
1 file changed
tree: b500f6a96a6d16cc64b7e68a56e405851a6b295a
  1. .buckconfig
  2. .gitignore
  3. BUCK
  4. lib/
  5. src/