Fix <operation> query AST node format

Author: Totktonada

graphql/core/parse.lua

@@ -150,6 +150,7 @@ local function cOperation(...)
 
     for i = 2, #args do
       -- key ~= nil => result['selectionSet'] = <...>
+      --            or result['name'] = <...>
       -- key == nil => result['variableDefinitions'] = <...>
       --            or result['directives'] = <...>
       local key = args[i].kind

graphql/core/validate.lua

@@ -51,6 +51,10 @@ local visitors = {
   -- {
   --   kind = 'operation',
   --   operation = 'query' or 'mutation',
+  --   name = {
+  --     kind = 'name',
+  --     value = <string>,
+  --   } (optional),
   --   selectionSet = <selectionSet>,
   --   variableDefinitions = list of <variableDefinition> (optional),
   --   directives = list of <directive> (optional),