Verify our implementation against sqlite

Sqlite is a large C codebase, so we can test our implementation of the parser and pretty printer by the following process:

```py
for file in sqlite:
  canonical_input = clang-format(file)
  our_output = lean_print(lean_parse(canonical_input))
  canonical_output = clang-format(our_output)
  assert canonical_input == canonical_output
```

