lsp: Show better info on IdentLiteral hover

Instead of showing the documentation for the expected type, show the
signature of the referenced object.

blueprintcompiler/language/gobject_object.py

@@ -55,6 +55,13 @@ class Object(AstNode):
     def content(self) -> ObjectContent:
         return self.children[ObjectContent][0]
 
+    @property
+    def signature(self) -> str:
+        if self.id:
+            return f"{self.class_name.gir_type.full_name} {self.id}"
+        else:
+            return f"{self.class_name.gir_type.full_name}"
+
     @property
     def gir_class(self) -> GirType:
         if self.class_name is None:

blueprintcompiler/language/gtk_list_item_factory.py

@@ -9,6 +9,14 @@ from .types import TypeName
 class ExtListItemFactory(AstNode):
     grammar = [UseExact("id", "template"), Optional(TypeName), ObjectContent]
 
+    @property
+    def id(self) -> str:
+        return "template"
+
+    @property
+    def signature(self) -> str:
+        return f"template {self.gir_class.full_name}"
+
     @property
     def type_name(self) -> T.Optional[TypeName]:
         if len(self.children[TypeName]) == 1:

blueprintcompiler/language/gtk_menu.py

@@ -35,6 +35,13 @@ class Menu(AstNode):
     def id(self) -> str:
         return self.tokens["id"]
 
+    @property
+    def signature(self) -> str:
+        if self.id:
+            return f"Gio.Menu {self.id}"
+        else:
+            return "Gio.Menu"
+
     @property
     def tag(self) -> str:
         return self.tokens["tag"]

blueprintcompiler/language/gtkbuilder_template.py

@@ -44,6 +44,13 @@ class Template(Object):
     def id(self) -> str:
         return "template"
 
+    @property
+    def signature(self) -> str:
+        if self.parent_type:
+            return f"template {self.gir_class.full_name} : {self.parent_type.gir_type.full_name}"
+        else:
+            return f"template {self.gir_class.full_name}"
+
     @property
     def gir_class(self) -> GirType:
         if isinstance(self.class_name.gir_type, ExternType):

blueprintcompiler/language/values.py

@@ -312,14 +312,20 @@ class IdentLiteral(AstNode):
 
     @docs()
     def docs(self) -> T.Optional[str]:
-        type = self.context[ValueTypeCtx].value_type
-        if isinstance(type, gir.Enumeration):
-            if member := type.members.get(self.ident):
+        expected_type = self.context[ValueTypeCtx].value_type
+        if isinstance(expected_type, gir.BoolType):
+            return None
+        elif isinstance(expected_type, gir.Enumeration):
+            if member := expected_type.members.get(self.ident):
                 return member.doc
             else:
-                return type.doc
-        elif isinstance(type, gir.GirNode):
-            return type.doc
+                return expected_type.doc
+        elif self.ident == "null" and self.context[ValueTypeCtx].allow_null:
+            return None
+        elif object := self.context[ScopeCtx].objects.get(self.ident):
+            return f"```\n{object.signature}\n```"
+        elif self.root.is_legacy_template(self.ident):
+            return f"```\n{self.root.template.signature}\n```"
         else:
             return None