Margin drift in large `these functions exist but are inaccessible` diagnostic

[Alexendoo]

In clippy if you add check() somewhere in clippy_lints where the function isn't found (e.g. in clippy_lints/src/lib.rs) the note will tell you about all the inaccessible functions called check of which there are many. That's handy, but there is a rather large margin applied to each function snippet. Starting in the ~middle there's a right to left 'sweep' of a veritcal bar in the multiline snippets

I tried to minimally reproduce this by putting 200/300 fn check {}s in their own modules but that didn't seem to work

Here's the output of cargo check on https://github.com/rust-lang/rust-clippy/commit/e120fb10c60a27670c72e7ec99e93d16c045f493 after adding check(); to clippy_lints/src/lib.rs: https://gist.github.com/Alexendoo/210cf32bd7e6248431604df767d2d13a