Empty String in attribute value should not remove it

[casid]

Especially for options this feature breaks the intent of the user:

@Test
void attributes_String_empty_option() {
    codeResolver.givenCode("template.jte", "@param String value\n<option value=\"${value}\">Click</option>");

    templateEngine.render("template.jte", "", output);

    assertThat(output.toString()).isEqualTo("<option value=\"\">Click</option>");
}

The actual output currently is:
<option>Click</option>

This is semantically different to the expected output:
<option value="">Click</option>

My proposed solution would be to remove String attributes only if the String is null. @kelunik I think you already suggested this already before.

[kelunik]

Indeed, that's how I thought I'd work.