Please set userdata.snippet in completed_item if the client support snippet

[Shougo]

It is to fix for neosnippet.

Related issue: #396

I have read the code and I found LanguageClient-neovim does not set snippet in user_data.
It should set.

Because, some LanguageClient does not support snippet like pyls.
But neosnippet does not know this candidate whether contains snippet.

From src/type.rs.

        let is_snippet;
        let snippet;
        if lspitem.insert_text_format == Some(InsertTextFormat::Snippet) {
            is_snippet = Some(true);
            snippet = Some(word.clone());
        } else {
            is_snippet = None;
            snippet = None;
        };

        let mut info = String::new();
        if let Some(ref doc) = lspitem.documentation {
            info += &doc.to_string();
        }

        let user_data = VimCompleteItemUserData {
            lspitem: Some(lspitem.clone()),
        };

        Ok(VimCompleteItem {
            word,
            abbr,
            icase: Some(1),
            dup: Some(1),
            menu: lspitem
                .detail
                .clone()
                .unwrap_or_default()
                .replace("\n", " "),
            info,
            kind: lspitem.kind.map(|k| format!("{:?}", k)).unwrap_or_default(),
            snippet,
            is_snippet,
            user_data: Some(serde_json::to_string(&user_data)?),
        })

Current user_data only set lspitem.
snippet and is_snippet information does not send to neosnippet.

[Shougo]

user_data.snippet should be empty if it does not support snippet.

The behavior is compatible with ncm2.

[autozimu]

Sure, I can make the change as long as there is a semi-consensus around how to use the user_data field.

[Shougo]

Thank you!