Quote schema comments

src/preserves/private/preserves_schema_nim.nim

@@ -269,7 +269,7 @@ proc generateConstProcs(result: var seq[PNode]; name: string; def: SchemaNode) =
       newEmpty(),
       newEmpty(),
       stmts)
-    constProc.comment = $def
+    constProc.comment = "``" & $def & "``"
     result.add constProc
   else: discard
 
@@ -448,7 +448,7 @@ proc generateNimFile*(scm: Schema; path: string) =
       var name = name
       name[0] = name[0].toUpperAscii
       let t = nimTypeOf(scm, knownTypes, def, name)
-      t.comment = $def
+      t.comment = "``" & $def & "``"
       case def.kind
       of snkAtom:
         knownTypes[name] = nkTypeDef.newNode.add(