Merge #630

630: Fill in DocumentSymbol::detail r=matklad a=hban

Closes: #516
I just pulled type text from the syntax node and "formatted" is bit. VS Code can't really handle multi-line symbol detail (it's will crop it when rendering), so that formatting will just collapse all white-space to singe space. It isn't pretty, but maybe there's a better way.

Issue also mentions "need to be done for `NavigationTarget` to `SymbolInformation`", but `SymbolInformation` doesn't have detail field on it?

Co-authored-by: Hrvoje Ban <hban@users.noreply.github.com>

diff --cc crates/ra_syntax/src/ast/generated.rs
Simple merge

diff --cc crates/ra_syntax/src/grammar.ron
Simple merge