doc/md: add info about using WhereInput as predicates (#2691)

* Add info about using `WhereInput` in with `.Where()`

* Update doc/md/predicates.md

Co-authored-by: Ariel Mashraki <7413593+a8m@users.noreply.github.com>

* Update tutorial-todo-gql-filter-input.md

* Update predicates.md

* Update predicates.md

* Update tutorial-todo-gql-filter-input.md

Co-authored-by: Ariel Mashraki <7413593+a8m@users.noreply.github.com>

doc/md/tutorial-todo-gql-filter-input.md

@@ -311,6 +311,19 @@ We can use this new filtering as any other predicate:
 }
 ```
 
+### Usage of filter inputs as predicates
+
+The `Filter` option lets use the generated `WhereInput`s as regular repdicates on any type of query:
+
+```go
+query := ent.Todo.Query()
+query, err := input.Filter(query)
+if err != nil {
+	return nil, err
+}
+return query.All(ctx)
+```
+
 ---
 
 Well done! As you can see, by changing a few lines of code our application now exposes a type-safe GraphQL filters