Some improvements to the boxed signatures in the docs (#6593)

* Show a more reasonable name in function docs

Signed-off-by: Nick Cameron <nrc@ncameron.org>

* Fix buggy docs for union types

Signed-off-by: Nick Cameron <nrc@ncameron.org>

* Make types in the docs signatures into links

Signed-off-by: Nick Cameron <nrc@ncameron.org>

---------

Signed-off-by: Nick Cameron <nrc@ncameron.org>

rust/kcl-lib/src/parsing/ast/types/mod.rs

@@ -783,6 +783,15 @@ impl BodyItem {
             BodyItem::ReturnStatement(node) => (node.comment_start, node.start),
         }
     }
+
+    pub(crate) fn visibility(&self) -> ItemVisibility {
+        match self {
+            BodyItem::ImportStatement(node) => node.visibility,
+            BodyItem::VariableDeclaration(node) => node.visibility,
+            BodyItem::TypeDeclaration(node) => node.visibility,
+            BodyItem::ExpressionStatement(_) | BodyItem::ReturnStatement(_) => ItemVisibility::Default,
+        }
+    }
 }
 
 impl From<BodyItem> for SourceRange {
@@ -1917,6 +1926,12 @@ pub struct TypeDeclaration {
     pub digest: Option<Digest>,
 }
 
+impl TypeDeclaration {
+    pub(crate) fn name(&self) -> &str {
+        &self.name.name
+    }
+}
+
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS, JsonSchema)]
 #[ts(export)]
 #[serde(tag = "type")]
@@ -1996,6 +2011,10 @@ impl VariableDeclaration {
         }
     }
 
+    pub(crate) fn name(&self) -> &str {
+        &self.declaration.id.name
+    }
+
     pub fn replace_value(&mut self, source_range: SourceRange, new_value: Expr) {
         self.declaration.init.replace_value(source_range, new_value.clone());
     }