Key options for failing proofs prompt aren't conventional.

```
Some proofs are failing. [A]ccept these changes or [C]ancel?:
Some proofs are failing. [A]ccept these changes or [C]ancel? (A, C):
```

The unix convention is that the casing of the input to a prompt is ignored; and further that the default value (the one that would be used if a user just presses `Enter`) is the only one listed in uppercase.

It appears that this message does not have a default so I would expect the prompts to be:

```
Some proofs are failing. [a]ccept these changes or [c]ancel?:
Some proofs are failing. [a]ccept these changes or [c]ancel? [a/c]:
```

As an enhancement, perhaps make one of the options a default?

Start by locating the client code that formats the failing-proofs prompt and check how its accepted options and default are represented. Done means the prompt follows the stated Unix casing convention and either documents or implements a clear default option, with coverage for the displayed wording.

Written by the indexing model from the issue text.