Add docstrings to schema.capnp

c++/src/capnp/schema.capnp

@@ -171,6 +171,19 @@ struct Node {
   }
 }
 
+struct NodeDoc {
+  # separate carrier for documentation comments on Nodes,
+  # to keep them out of the binary descriptors
+
+  id @0 :Id;
+  # ID should exist as Node in the same request
+
+  docComment @1 :Text;
+
+  fieldDocs @2 :List(FieldDoc);
+  # valid only if Node is a "struct"
+}
+
 struct Field {
   # Schema for a field of a struct.
 
@@ -229,6 +242,13 @@ struct Field {
   }
 }
 
+struct FieldDoc {
+  # separate container to carry field docstrings
+
+  codeOrder @0 :UInt16;
+  docComment @1 :Text;
+}
+
 struct Enumerant {
   # Schema for member of an enum.
 
@@ -468,6 +488,9 @@ struct CodeGeneratorRequest {
   # All nodes parsed by the compiler, including for the files on the command line and their
   # imports.
 
+  nodeDocs @3 :List(NodeDoc);
+  # documentation comments for nodes, where present
+
   requestedFiles @1 :List(RequestedFile);
   # Files which were listed on the command line.