Fix completion details on new clangd versions

[BorisVassilev1]

Fixes #16057

In newer versions of clangd, the switch labelDetailsSupport in the json passed to the language server modifies the format of the returned json. Zed handles well the old format, but misses the function parameters in the new one. For example:
The old format looks like this:

...
"label": " Window(int width, int height, const char *name, bool vsync, bool resizable)",
...

and with labelDetailsSupport = true:

...
 "label": " Window",
 "labelDetails": {
     "detail": "(int width, int height, const char *name, bool vsync, bool resizable)"
 },
...

A simple solution is to just to not tell the language server that label details are supported and force it to use the old format. This is a dirty fix, but makes the completions behave like in the old versions of clangd.

I do not know if this will break another language server. From what I've found out most lsp-s do not depend on that setting and provide all completion data either way. If not, this switch will need to be exposed in a config or be at least lsp-dependant.

Lastly, I do not know Rust, maybe will need help to make a better fix for the issue.

Release Notes:

• Fixed broken C++ completion suggestions

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[BorisVassilev1]

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[maxdeviant]

I do not know if this will break another language server.

There are other language servers that do depend on labelDetails, so this will certainly break them.

We'll need to find an alternative solution. Since this is related to a change in clangd, then the fix should be made accordingly in the code that deals specifically with clangd.

Here is where we construct the completion menu labels for clangd:

zed/crates/languages/src/c.rs

Lines 118 to 201 in 04732b2

	async fn label_for_completion(
	&self,
	completion: &lsp::CompletionItem,
	language: &Arc<Language>,
	) -> Option<CodeLabel> {
	let label = completion
	.label
	.strip_prefix('•')
	.unwrap_or(&completion.label)
	.trim();
	match completion.kind {
	Some(lsp::CompletionItemKind::FIELD) if completion.detail.is_some() => {
	let detail = completion.detail.as_ref().unwrap();
	let text = format!("{} {}", detail, label);
	let source = Rope::from(format!("struct S {{ {} }}", text).as_str());
	let runs = language.highlight_text(&source, 11..11 + text.len());
	return Some(CodeLabel {
	filter_range: detail.len() + 1..text.len(),
	text,
	runs,
	});
	}
	Some(lsp::CompletionItemKind::CONSTANT | lsp::CompletionItemKind::VARIABLE)
	if completion.detail.is_some() =>
	{
	let detail = completion.detail.as_ref().unwrap();
	let text = format!("{} {}", detail, label);
	let runs = language.highlight_text(&Rope::from(text.as_str()), 0..text.len());
	return Some(CodeLabel {
	filter_range: detail.len() + 1..text.len(),
	text,
	runs,
	});
	}
	Some(lsp::CompletionItemKind::FUNCTION | lsp::CompletionItemKind::METHOD)
	if completion.detail.is_some() =>
	{
	let detail = completion.detail.as_ref().unwrap();
	let text = format!("{} {}", detail, label);
	let runs = language.highlight_text(&Rope::from(text.as_str()), 0..text.len());
	let filter_start = detail.len() + 1;
	let filter_end =
	if let Some(end) = text.rfind('(').filter(|end| *end > filter_start) {
	end
	} else {
	text.len()
	};
	return Some(CodeLabel {
	filter_range: filter_start..filter_end,
	text,
	runs,
	});
	}
	Some(kind) => {
	let highlight_name = match kind {
	lsp::CompletionItemKind::STRUCT
	| lsp::CompletionItemKind::INTERFACE
	| lsp::CompletionItemKind::CLASS
	| lsp::CompletionItemKind::ENUM => Some("type"),
	lsp::CompletionItemKind::ENUM_MEMBER => Some("variant"),
	lsp::CompletionItemKind::KEYWORD => Some("keyword"),
	lsp::CompletionItemKind::VALUE | lsp::CompletionItemKind::CONSTANT => {
	Some("constant")
	}
	_ => None,
	};
	if let Some(highlight_id) = language
	.grammar()
	.and_then(|g| g.highlight_id_for_name(highlight_name?))
	{
	let mut label = CodeLabel::plain(label.to_string(), None);
	label.runs.push((
	0..label.text.rfind('(').unwrap_or(label.text.len()),
	highlight_id,
	));
	return Some(label);
	}
	}
	_ => {}
	}
	Some(CodeLabel::plain(label.to_string(), None))
	}

[BorisVassilev1]

I don't know if this is the 'rustacean' way of doing this, but 'works on my machine'.

I have not been able to make all tests pass on my machine (even with a freshly cloned repository). I have followed all instructions (except those regarding collaboration (local server and such). Will have to rely on workflows.

How do I trigger workflows again? -> Edit: they were queued already.