submodules: update rls from 6f5e4bb to 1a6361b

Changes:
````
Update Clippy
Move TestFailures when collecting failures
Update languageserver-types to 0.51.1
update clippy hash and rustc_tools_util and use rustc_tools_util from crates.io
Work around https://github.com/rust-lang/rust/pull/55937
Update Clippy... again
Update Clippy
Update clippy
````