Make use of the new 'abstract' builtin annotation

Author: khellste

addons/kodot/tools/annotations/annotation.gd

@@ -1,3 +1,4 @@
+@abstract
 @tool
 class_name Annotation
 extends RefCounted
@@ -30,13 +31,13 @@ func find_in_tree(tree: TreeSitterSyntaxTree) -> Array:
 
 ## Gets the TreeSitter query which selects this annotation from a GDScript
 ## syntax tree.
-func _get_query_template() -> String:
-    return Errors.abstract_method("_get_query_template")
+@abstract
+func _get_query_template() -> String
 
 
 ## Parses annotation-specific metadata from a TreeSitter query match.
-func _from_match(query_match: Dictionary) -> Dictionary:
-    return Errors.abstract_method("_from_match")
+@abstract
+func _from_match(query_match: Dictionary) -> Dictionary
 
 
 func _from_match_adding_argument(query_match: Dictionary) -> Dictionary:

addons/kodot/tools/codegen/codegen.gd

@@ -1,3 +1,4 @@
+@abstract
 @tool
 class_name Codegen
 extends RefCounted
@@ -11,14 +12,14 @@ static func _load_template(path: String) -> InjaTemplate:
 
 
 ## Which annotations, if any, are used by this Codegen.
-func get_required_annotations() -> Array[Annotation]:
-    return Errors.abstract_method("get_required_annotations")
+@abstract
+func get_required_annotations() -> Array[Annotation]
 
 
 ## Generate units of code from the given GDScript resource.
+@abstract
 func get_codegen_units(
-        script: GDScript, annotations: Annotations) -> Array[Unit]:
-    return Errors.abstract_method("get_codegen_units")
+        script: GDScript, annotations: Annotations) -> Array[Unit]
 
 
 class Unit:

addons/kodot/tools/codegen/writers/codegen_writer.gd

@@ -1,9 +1,10 @@
+@abstract
 @tool
 class_name CodegenWriter
 extends RefCounted
 
 ## An abstract generated code writer which can, e.g., write to a file.
 
 
-func write(new_source: String) -> bool:
-    return Errors.abstract_method("write")
+@abstract
+func write(new_source: String) -> bool

addons/kodot/tools/script_processor.gd

@@ -1,3 +1,4 @@
+@abstract
 @tool
 class_name ScriptProcessor
 extends RefCounted
@@ -46,5 +47,5 @@ func apply_to_project() -> void:
 
 
 ## Acts on a single GDSCript source.
-func apply_to_script(script: GDScript) -> void:
-    Errors.abstract_method("apply_to_script")
+@abstract
+func apply_to_script(script: GDScript) -> void