dev: more consistent way to get docs of decls (#752)

* dev: more consistent way to get docs of decls

* test: update snapshot

crates/tinymist-query/src/signature_help.rs

@@ -3,9 +3,11 @@ use typst_shim::syntax::LinkedNodeExt;
 
 use crate::{
     adt::interner::Interned,
+    analysis::Definition,
     prelude::*,
-    syntax::{get_check_target, get_deref_target, CheckTarget, ParamTarget},
-    DocTooltip, LspParamInfo, SemanticRequest,
+    syntax::{find_docs_before, get_check_target, get_deref_target, CheckTarget, ParamTarget},
+    upstream::plain_docs_sentence,
+    LspParamInfo, SemanticRequest,
 };
 
 /// The [`textDocument/signatureHelp`] request is sent from the client to the
@@ -40,7 +42,7 @@ impl SemanticRequest for SignatureHelpRequest {
 
         let deref_target = get_deref_target(callee, cursor)?;
 
-        let def_link = ctx.definition(&source, None, deref_target)?;
+        let def_link = ctx.def_of_syntax(&source, None, deref_target)?;
 
         let documentation = DocTooltip::get(ctx, &def_link)
             .as_deref()
@@ -59,7 +61,7 @@ impl SemanticRequest for SignatureHelpRequest {
             function = &inner.0;
         }
 
-        let sig = ctx.signature_dyn(function.clone());
+        let sig = ctx.sig_of_func(function.clone());
 
         log::debug!("got signature {sig:?}");
 
@@ -145,6 +147,54 @@ impl SemanticRequest for SignatureHelpRequest {
     }
 }
 
+pub(crate) struct DocTooltip;
+
+impl DocTooltip {
+    pub fn get(ctx: &mut AnalysisContext, def: &Definition) -> Option<String> {
+        self::DocTooltip::get_inner(ctx, def).map(|s| "\n\n".to_owned() + &s)
+    }
+
+    fn get_inner(ctx: &mut AnalysisContext, def: &Definition) -> Option<String> {
+        let value = def.value();
+        if matches!(value, Some(Value::Func(..))) {
+            if let Some(builtin) = Self::builtin_func_tooltip(def) {
+                return Some(plain_docs_sentence(builtin).into());
+            }
+        };
+
+        let (fid, def_range) = def.def_at(ctx.shared()).clone()?;
+
+        let src = ctx.source_by_id(fid).ok()?;
+        find_docs_before(&src, def_range.start)
+    }
+}
+
+impl DocTooltip {
+    fn builtin_func_tooltip(def: &Definition) -> Option<&'_ str> {
+        let value = def.value();
+        let Some(Value::Func(func)) = &value else {
+            return None;
+        };
+
+        use typst::foundations::func::Repr;
+        let mut func = func;
+        let docs = 'search: loop {
+            match func.inner() {
+                Repr::Native(n) => break 'search n.docs,
+                Repr::Element(e) => break 'search e.docs(),
+                Repr::With(w) => {
+                    func = &w.0;
+                }
+                Repr::Closure(..) => {
+                    return None;
+                }
+            }
+        };
+
+        Some(docs)
+    }
+}
+
 fn markdown_docs(docs: &str) -> Documentation {
     Documentation::MarkupContent(MarkupContent {
         kind: MarkupKind::Markdown,