Previously the `call` helper (and its related functions) returned a
`serde_json::Value` which was then decoded either later in the client
(see signature help and hover) or by the client's caller. This led to
some unnecessary boilerplate in the client:
let resp = self.call::<MyRequest>(params);
Some(async move { Ok(serde_json::from_value(resp.await?)?) })
and in the caller. It also allowed for mistakes with the types. The
workspace symbol request's calling code for example mistakenly decoded a
`lsp::WorkspaceSymbolResponse` as `Vec<lsp::SymbolInformation>` - one of
the untagged enum members (so it parsed successfully) but not the
correct type.
With this change, the `call` helper eagerly decodes the response to a
request as the `lsp::request::Request::Result` trait item. This is
similar to the old helper `request` (which has become redundant and has
been eliminated) but all work is done within the same async block which
avoids some awkward lifetimes. The return types of functions like
`Client::text_document_range_inlay_hints` are now more verbose but it is
no longer possible to accidentally decode as an incorrect type.
Additionally `Client::resolve_code_action` now uses the `call_with_ref`
helper to avoid an unnecessary clone.