Tweak GraphQL board description

app/graphql/types/board_type.rb

@@ -15,7 +15,7 @@ module Types
     field :lists,
           Types::BoardListType.connection_type,
           null: true,
-          description: 'Lists of the project board',
+          description: 'Lists of the board',
           resolver: Resolvers::BoardListsResolver,
           extras: [:lookahead]
   end

doc/api/graphql/reference/gitlab_schema.graphql

@@ -591,7 +591,7 @@ type Board {
   id: ID!
 
   """
-  Lists of the project board
+  Lists of the board
   """
   lists(
     """

doc/api/graphql/reference/gitlab_schema.json

@@ -1541,7 +1541,7 @@
             },
             {
               "name": "lists",
-              "description": "Lists of the project board",
+              "description": "Lists of the board",
               "args": [
                 {
                   "name": "after",