Add structure markers to SyntaxNodes.swift.gyb

Author: ahoppen

Sources/SwiftSyntax/SyntaxNodes.swift.gyb

@@ -52,6 +52,10 @@ Each node will have:
 /// ${line}
 %     end
 public struct ${node.name}: ${base_type}Protocol {
+%     # ======
+%     # Cursor
+%     # ======
+%
 %     if node.children:
   enum Cursor: Int {
 %       for child in node.children:
@@ -60,6 +64,10 @@ public struct ${node.name}: ${base_type}Protocol {
   }
 %     end
 
+%     # ==============
+%     # Initialization
+%     # ==============
+%
   public let _syntaxNode: Syntax
 
   /// Converts the given `Syntax` node to a `${node.name}` if possible. Returns
@@ -79,10 +87,16 @@ public struct ${node.name}: ${base_type}Protocol {
 
 %     for child in node.children:
 %       child_node = NODE_MAP.get(child.syntax_kind)
+%
+%       # ===================
+%       # Children properties
+%       # ===================
+%
 %       ret_type = child.type_name
 %       if child.is_optional:
 %         ret_type += '?'
 %       end
+
 %       for line in dedented_lines(child.description):
   /// ${line}
 %       end
@@ -99,6 +113,10 @@ public struct ${node.name}: ${base_type}Protocol {
       self = with${child.name}(value)
     }
   }
+%
+%       # ===============
+%       # Adding children
+%       # ===============
 %       if child_node and child_node.is_syntax_collection():
 %         child_elt = child.collection_element_name
 %         child_elt_type = child_node.collection_element_type
@@ -126,6 +144,9 @@ public struct ${node.name}: ${base_type}Protocol {
   }
 %       end
 
+%       # ===================
+%       # Replacing children
+%       # ===================
   /// Returns a copy of the receiver with its `${child.swift_name}` replaced.
   /// - param newChild: The new `${child.swift_name}` to replace the node's
   ///                   current `${child.swift_name}`, if present.