test_tooltip_std test failing

[MingweiSamuel]

Build is working again but the test_tooltip_std is failing (https://github.com/rust-lang/rls/actions/runs/1702875684). Some tooltips are missing from the actual output (❌):

✅: Test { file: "test_tooltip_std.rs", line: 8, col: 15 }
❌: Test { file: "test_tooltip_std.rs", line: 8, col: 27 }
✅: Test { file: "test_tooltip_std.rs", line: 9, col: 7 }
❌: Test { file: "test_tooltip_std.rs", line: 9, col: 12 }
✅: Test { file: "test_tooltip_std.rs", line: 10, col: 12 }
✅: Test { file: "test_tooltip_std.rs", line: 10, col: 20 }
❌: Test { file: "test_tooltip_std.rs", line: 11, col: 25 }
❌: Test { file: "test_tooltip_std.rs", line: 12, col: 33 }
✅: Test { file: "test_tooltip_std.rs", line: 13, col: 11 }
✅: Test { file: "test_tooltip_std.rs", line: 13, col: 18 }
✅: Test { file: "test_tooltip_std.rs", line: 14, col: 24 }
❌: Test { file: "test_tooltip_std.rs", line: 15, col: 17 }
❌: Test { file: "test_tooltip_std.rs", line: 15, col: 25 }

I took a look at it but I'm not familiar enough with the code to know what might cause this. I'm also not really sure why the triggered CI succeeds (scheduled CI fails)---my local build is always failing these tests. The scheduled CI is also failing test_tooltip_std_racer but that seems to pass for me locally.

Locally, the rest of the tests are all passing so this is the last thing to fix right now

[calebcartwright]

FWIW those tests can be somewhat brittle because many are based on upstream values in rustc that can be changed independently. Fixing them typically involves updating the expected test fixture(s) to account for upstream doc changes, you can find a few references of this in the commit history https://github.com/rust-lang/rls/commits/master/tests/fixtures, e.g. d9d15369a58706e181af5b790f693ee32d9782c9 or bf446723cb60521a6ceee36254b7137f520dc98e