Change docs links to actual file extension (.md)

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

Change-Id: I8fd98395cf7aebb1dfe06c223a3c75b85b6fcddd
1 file changed
tree: c91f46fea448c9fc3990e18805e6b03c19135a41
  1. lib/
  2. src/
  3. .buckconfig
  4. .gitignore
  5. BUCK