A few additions:
- Lines with `{{`: These can show up if serializing non-MLIR info into
string attrs `my.attr = {{proto}, {...}}`. String escape the opening
`{{`, given that check lines are generated this has no effect on
`{{.*}}` etc in generated lines.
- File split line: Normally these are skipped because of their indent
level, but if using `--starts_from_scope=0` to generate checks for the
`module {...} {` line, and since MLIR opt tools emit file split lines by
default, some `CHECK: // -----` lines were emit.
- (edit removed this, fixed by
https://github.com/llvm/llvm-project/pull/134364) AttrAliases: I'm not
sure if I'm missing something for the attribute parser to work
correctly, but I was getting many `#[[?]]` for all dialect attrs. Only
use the attr aliasing if there's a match.