static void fixReservedIdentifiers(Map<?, String> methodToIdentifier) {
    for (Map.Entry<?, String> entry : methodToIdentifier.entrySet()) {
      String name = entry.getValue();
      if (SourceVersion.isKeyword(name) || !Character.isJavaIdentifierStart(name.codePointAt(0))) {
        entry.setValue(disambiguate(name, methodToIdentifier.values()));
      }
    }
  }
Modifies the values of the given map to avoid reserved words. If we have a getter called {@code
getPackage()} then we can't use the identifier {@code package} to represent its value since
that's a reserved word.
value/src/main/java/com/google/auto/value/processor/AutoValueishProcessor.java