Inconsistent property name of value argument

[shanretoo]

The documentation specifies the property name for the type associated with the value argument as Type, yet in the codebase, this property is actually named value. This inconsistency could lead to confusion.

https://github.com/substrait-io/substrait/blob/3dc77aeca820eba70ba141bf3afa5e4c5ba055b9/site/docs/expressions/scalar_functions.md#L27-L32

https://github.com/substrait-io/substrait/blob/3dc77aeca820eba70ba141bf3afa5e4c5ba055b9/text/simple_extensions_schema.yaml#L114-L122

In substrait-java:

  public abstract static class ValueArgument implements Argument {

    @JsonProperty(required = true)
    public abstract ParameterizedType value();