A single <xf> record from cellXfs. Cells reference these by index via
the s attribute (<c r="A1" s="3"/> → cell_formats[3]).
Summary
Types
@type t() :: %ExVEx.OOXML.Styles.CellFormat{ alignment: ExVEx.OOXML.Styles.AlignmentRecord.t() | nil, border_id: non_neg_integer(), fill_id: non_neg_integer(), font_id: non_neg_integer(), num_fmt_id: non_neg_integer(), xf_id: non_neg_integer() }