`cargo test --release` fails

Hello,

I tried running the unit tests as described in the README, but they seem to fail during the doctests.

I've tested using an x86 Ubuntu 24.04 LTS machine.

```
Doc-tests ccc

running 4 tests
test src/backend/traits.rs - backend::traits::delegate_to_impl (line 29) ... ignored
test src/passes/if_convert.rs - passes::if_convert::detect_triangle (line 404) ... FAILED
test src/passes/if_convert.rs - passes::if_convert (line 23) ... FAILED
test src/passes/if_convert.rs - passes::if_convert (line 5) ... FAILED

failures:

---- src/passes/if_convert.rs - passes::if_convert::detect_triangle (line 404) stdout ----
error: expected one of `!` or `::`, found `:`
--> src/passes/if_convert.rs:405:5
|
1 | pred: CondBranch(cond, arm, merge) -- or (cond, merge, arm)
| ^ expected one of `!` or `::`

error: aborting due to 1 previous error

Couldn't compile the test.
---- src/passes/if_convert.rs - passes::if_convert (line 23) stdout ----
error: expected one of `!` or `::`, found `:`
--> src/passes/if_convert.rs:24:11
|
1 | pred_block:
| ^ expected one of `!` or `::`

error: aborting due to 1 previous error

Couldn't compile the test.
---- src/passes/if_convert.rs - passes::if_convert (line 5) stdout ----
error: expected one of `!` or `::`, found `:`
--> src/passes/if_convert.rs:6:11
|
1 | pred_block:
| ^ expected one of `!` or `::`

error: aborting due to 1 previous error

Couldn't compile the test.

failures:
src/passes/if_convert.rs - passes::if_convert (line 23)
src/passes/if_convert.rs - passes::if_convert (line 5)
src/passes/if_convert.rs - passes::if_convert::detect_triangle (line 404)

test result: FAILED. 0 passed; 3 failed; 1 ignored; 0 measured; 0 filtered out; finished in 0.01s

error: doctest failed, to rerun pass `--doc`

```