The line separator is moved below the function signature to split
regions between the docs. This is very similar to how IntelliJ
displays tooltips. Adding an additional separator between the module
name and function signature currently has rendering issues.
Fixes#4594
Alternative to #4615
This also changes our handiling of snippet edits on the client side.
`editor.insertSnippet` unfortunately forces indentation, which we
really don't want to have to deal with. So, let's just implement our
manual hacky way of dealing with a simple subset of snippets we
actually use in rust-analyzer
In general, there should be no reason to call `.to_string_lossy`.
If you want to display the path, use `.display()`.
If you want to pass the path to an OS API (like std::process::Command)
than use `PathBuf` or `OsString`.
