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. .buckconfig
  2. .gitignore
  3. BUCK
  4. lib/
  5. src/