I think previous input for filter-recursion ui test was not right as it
was not triggering error for recursion itself, for example:
```rust
fn fuzzed_filter_recursion() {
const TEMPLATE: &str = include_str!("../tests/filter-recursion.txt");
if let Err(e) = Ast::from_str(TEMPLATE, None, &Syntax::default()) {
panic!("{e}");
}
}
```
```sh
---- tests::fuzzed_filter_recursion stdout ----
thread 'tests::fuzzed_filter_recursion' panicked at rinja_parser/src/tests.rs:1121:9:
failed to parse template source at row 1, column 255 near:
"|A|AA|A|A|A|A|AA|A|A|A|A|AA|A|A|A|A|AA|A"...
```
4dee4e747f