entgql: use dynamic Value/GetValue method name in pagination with edge order fields (#603)

Updates to use the `ValueName` method to get the name of the dynamic
`Value`/`GetValue` method name for a type instead of using the
hard-coded name `Value` in the `pagination.tmpl` file.

Author: henrywoody

entgql/internal/todo/ent.graphql

@@ -318,6 +318,7 @@ input CreateTodoInput {
   priority: Int
   text: String!
   init: Map
+  value: Int
   parentID: ID
   childIDs: [ID!]
   categoryID: ID
@@ -974,6 +975,7 @@ type Todo implements Node {
   init: Map
   custom: [Custom!]
   customp: [Custom]
+  value: Int!
   parent: Todo
   children(
     """
@@ -1145,6 +1147,17 @@ input TodoWhereInput {
   categoryIDIsNil: Boolean
   categoryIDNotNil: Boolean
   """
+  value field predicates
+  """
+  value: Int
+  valueNEQ: Int
+  valueIn: [Int!]
+  valueNotIn: [Int!]
+  valueGT: Int
+  valueGTE: Int
+  valueLT: Int
+  valueLTE: Int
+  """
   parent edge predicates
   """
   hasParent: Boolean
@@ -1208,6 +1221,7 @@ input UpdateTodoInput {
   text: String
   init: Map
   clearInit: Boolean
+  value: Int
   parentID: ID
   clearParent: Boolean
   addChildIDs: [ID!]