5694: Format docs in to_proto::markup_content r=jonas-schievink a=JmPotato
Signed-off-by: JmPotato <ghzpotato@gmail.com>
Close #5442
Removing # was handled in rust_analyzer::markdown::format_docs(). However, this function is no longer called in rust_analyzer::handlers::handle_hover() since commit
e8bb153 (PR #5273). This pr add this formatting function back.
Co-authored-by: JmPotato <ghzpotato@gmail.com>