Update Racer and Rustfmt

[Xanewok]

Needs a Racer release including the racer-rust/racer#1000
cc @kngwyu

@nrc this has the remaining impls. Still fails on:

failures:

---- test::test_goto_def stdout ----
thread 'test::test_goto_def' panicked at 'Assert failed: Could not find `"start":{"line":20,"character":8}` in `{"jsonrpc":"2.0","id":11,"result":[]}`', src/test/harness.rs:227:9

---- test::test_hover stdout ----
thread 'test::test_hover' panicked at 'Assert failed: Could not find `[{"language":"rust","value":"&str"},{"language":"rust","value":"let world = \"world\";"}]` in `{"jsonrpc":"2.0","id":11,"result":{"contents":[]}}`', src/test/harness.rs:227:9

---- test::test_highlight stdout ----
thread 'test::test_highlight' panicked at 'Assert failed: Could not find `{"start":{"line":20,"character":8},"end":{"line":20,"character":13}}` in `{"jsonrpc":"2.0","id":42,"result":[]}`', src/test/harness.rs:227:9

---- test::test_rename stdout ----
thread 'test::test_rename' panicked at 'Assert failed: Could not find `{"start":{"line":20,"character":8},"end":{"line":20,"character":13}}` in `{"jsonrpc":"2.0","id":42,"result":{}}`', src/test/harness.rs:227:9


failures:
    test::test_goto_def
    test::test_highlight
    test::test_hover
    test::test_rename

but that's until rust-lang/rust#55936 lands, right?

[Xanewok]

@kngwyu do I understand that in this case, we have use X as Y and we match on Y but m here refers to X and we can derive the completion kind from that instead? (also nested/recursive case seems to be impossible?)

[kngwyu]

I think it's impossible too but haven't tested it yet.

[Xanewok]

All tests pass locally with Rust with rust-lang/rust#55936 applied 🎉

[nrc]

Awesome, thanks!