Need add more information for introspected FieldElement about micronaut-core

[altro3]

Maybe the best solution is just add new VariableDeclarationElement:

[altro3]

Ok, understand what we need to do: just need to add new method Object getConstantValue() for FieldElement interface. Look to javax.lang.model.element.VariableElement:

    /**
     * Returns the value of this variable if this is a {@code final}
     * field initialized to a compile-time constant.  Returns {@code
     * null} otherwise.  The value will be of a primitive type or a
     * {@code String}.  If the value is of a primitive type, it is
     * wrapped in the appropriate wrapper class (such as {@link
     * Integer}).
     *
     * <p>Note that not all {@code final} fields will have
     * constant values.  In particular, {@code enum} constants are
     * <em>not</em> considered to be compile-time constants.  To have a
     * constant value, a field's type must be either a primitive type
     * or {@code String}.
     *
     * @return the value of this variable if this is a {@code final}
     * field initialized to a compile-time constant, or {@code null}
     * otherwise
     *
     * @see Elements#getConstantExpression(Object)
     * @jls 15.29 Constant Expressions
     * @jls 4.12.4 final Variables
     */
    Object getConstantValue();

[dstepanov]

Please create a PR.

[altro3]

@dstepanov done