message: Reformat more code to one import per line
  Summary:
  `./test.py --rustfmt-only` does not reformat these (don't know why).
  This is preparation to reformat whole fbsource.
  ```
  find fbcode/buck2 -name '*.rs' | xargs arc rustfmt --config group_imports=StdExternalCrate,imports_granularity=Item
  ```
diff: //! Based on the reference lsp-server example at <https://github.com/rust-analyzer/lsp-server/blob/master/examples/goto_def.rs>.
  -use std::{
  - collections::HashMap,
  - sync::{Arc, RwLock},
  -};
  +use std::collections::HashMap;
  +use std::sync::Arc;
  +use std::sync::RwLock;
  use gazebo::prelude::*;
  -use lsp_server::{Connection, Message, Notification, Request, RequestId, Response};
  -use lsp_types::{
  - notification::{
  - DidChangeTextDocument, DidCloseTextDocument, DidOpenTextDocument, LogMessage,
  - PublishDiagnostics,
  - },
  - request::GotoDefinition,
  - DefinitionOptions, Diagnostic, DidChangeTextDocumentParams, DidCloseTextDocumentParams,
  - DidOpenTextDocumentParams, GotoDefinitionParams, GotoDefinitionResponse, InitializeParams,
  - Location, LogMessageParams, MessageType, OneOf, PublishDiagnosticsParams, ServerCapabilities,
  - TextDocumentSyncCapability, TextDocumentSyncKind, Url, WorkDoneProgressOptions,
  -};
  +use lsp_server::Connection;
  +use lsp_server::Message;
  +use lsp_server::Notification;
  +use lsp_server::Request;
  +use lsp_server::RequestId;
  +use lsp_server::Response;
  +use lsp_types::notification::DidChangeTextDocument;
  +use lsp_types::notification::DidCloseTextDocument;
  +use lsp_types::notification::DidOpenTextDocument;
  +use lsp_types::notification::LogMessage;
  +use lsp_types::notification::PublishDiagnostics;
  +use lsp_types::request::GotoDefinition;
  +use lsp_types::DefinitionOptions;
  +use lsp_types::Diagnostic;
  +use lsp_types::DidChangeTextDocumentParams;
  +use lsp_types::DidCloseTextDocumentParams;
  +use lsp_types::DidOpenTextDocumentParams;
  +use lsp_types::GotoDefinitionParams;
  +use lsp_types::GotoDefinitionResponse;
  +use lsp_types::InitializeParams;
  +use lsp_types::Location;
  +use lsp_types::LogMessageParams;
  +use lsp_types::MessageType;
  +use lsp_types::OneOf;
  +use lsp_types::PublishDiagnosticsParams;
  +use lsp_types::ServerCapabilities;
  +use lsp_types::TextDocumentSyncCapability;
  +use lsp_types::TextDocumentSyncKind;
  +use lsp_types::Url;
  +use lsp_types::WorkDoneProgressOptions;
  use serde::de::DeserializeOwned;
  use starlark::syntax::AstModule;
  @@ -288,10 +305,15 @@ where
  #[cfg(test)]
  mod test {
  - use lsp_types::{
  - request::GotoDefinition, GotoDefinitionParams, GotoDefinitionResponse, Location, Position,
  - Range, TextDocumentIdentifier, TextDocumentPositionParams, Url,
  - };
  + use lsp_types::request::GotoDefinition;
  + use lsp_types::GotoDefinitionParams;
  + use lsp_types::GotoDefinitionResponse;
  + use lsp_types::Location;
  + use lsp_types::Position;
  + use lsp_types::Range;
  + use lsp_types::TextDocumentIdentifier;
  + use lsp_types::TextDocumentPositionParams;
  + use lsp_types::Url;
  use super::helpers::TestServer;
  