minor: Move json deserialization into text_document_hover future

This follows a pattern used in the signature help request for example.
Moving the json deserialization into the return future of
`text_document_hover` makes the types easier for callers to work with.

helix-lsp/src/client.rs

@@ -1119,7 +1119,7 @@ impl Client {
         text_document: lsp::TextDocumentIdentifier,
         position: lsp::Position,
         work_done_token: Option<lsp::ProgressToken>,
-    ) -> Option<impl Future<Output = Result<Value>>> {
+    ) -> Option<impl Future<Output = Result<Option<lsp::Hover>>>> {
         let capabilities = self.capabilities.get().unwrap();
 
         // Return early if the server does not support hover.
@@ -1140,7 +1140,8 @@ impl Client {
             // lsp::SignatureHelpContext
         };
 
-        Some(self.call::<lsp::request::HoverRequest>(params))
+        let res = self.call::<lsp::request::HoverRequest>(params);
+        Some(async move { Ok(serde_json::from_value(res.await?)?) })
     }
 
     // formatting

helix-term/src/commands/lsp.rs

@@ -1076,11 +1076,7 @@ pub fn hover(cx: &mut Context) {
                 .text_document_hover(doc.identifier(), pos, None)
                 .unwrap();
 
-            async move {
-                let json = request.await?;
-                let response = serde_json::from_value::<Option<lsp::Hover>>(json)?;
-                anyhow::Ok((server_name, response))
-            }
+            async move { anyhow::Ok((server_name, request.await?)) }
         })
         .collect();