function indentIfBreak(contents, opts) {
  assertDoc(contents);

  return {
    type: DOC_TYPE_INDENT_IF_BREAK,
    contents,
    groupId: opts.groupId,
    negate: opts.negate,
  };
}
Optimized version of `ifBreak(indent(doc), doc, { groupId: ... })`
@param {Doc} contents
@param {{ groupId: symbol, negate?: boolean }} opts
@returns Doc