Omit the redundant method isReal() to make it simpler

[tosukriti]

Omit the redundant method isReal() to make it simpler since we can directly compare the enum instance with ==

https://github.com/google/google-java-format/blob/18f835849551f81d60d582300a0a3c585b5774b4/core/src/main/java/com/google/googlejavaformat/Doc.java#L394