Use visit_expr_field for ParamPosition

[Alexendoo]

A small change to make it a little simpler

changelog: none

[rust-highfive]

r? @giraffate

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[giraffate]

@bors r+

It looks good, thanks!

[bors]

📌 Commit 1b245e7 has been approved by giraffate

It is now in the queue for this repository.

[bors]

⌛ Testing commit 1b245e7 with merge 018b54b...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: giraffate
Pushing 018b54b to master...

[nyurik]

I think this PR broke format parsing. To test, add this to tests/ui/explicit_write.rs (e.g. around line 39) -- before this PR, it would suggest a replacement with eprintln!("{:w$}", val, w = width);, but now it fails to parse and silently ignores.

        let val = 1;
        let width = 2;
        writeln!(std::io::stderr(), "{:w$}", val, w = width).unwrap();